Re: Questions looking for answers

[Guest guest]

The reason is that as you walk, you are burning up glucose. so if your

glucose is too low when you start exercising, it drops and your body puts

out glucogon fro the liver to bring it up-only it puts out too much, hence

the higher sugars. It make syou feel tired then and until it drops, you

feel like you are beat because your normally low BG has gone so high. I

know I do not have to have what some diabetics call an okay sugar too feel

tired. consistantly high blood sugars make people feel tired and

un-motivated. there are 3 ladies in my new diabetic class who feel like

that all the time. They have BMI's in the 30's and A1C's over 9!

You and I who have pretty much normal BG's feel like they do if our BG's go

over 150.

Questions looking for answers

What causes this?

First, I will note the following observation regarding my glucose level

reading and exercise:

Prior to exercising for an hour and fifteen minutes, which includes walking

approximately 1.9 miles and several sets of isometric exercises,

a glucose of 120 or less yields a post exercise glucose reading of 160 plus

or minus 10 points, and I feel exhausted for a long time.

If I have a pre-exercise glucose level reading of 150 to 160, my post

exercise glucose level reading is usually around 75 plus or minus 10 points,

and I feel fairly good.

Do others experience this?

What are the explanations for these observations? Post this message to

other forums if you wish. I would really like to know.

[Guest guest]

Thanks for your response, which prompted me to do more research on

the internet. I found the following, which is a good primmer on metabolism

and diabetes in normal people. I like your simple explanation much better

than the one presented below:

The Pancreas

The topic of insulin and glucagon begins here, in the pancreas.The pancreas

is located in the abdominal cavity adjacent to the upper part of the small

intestine

as shown in the diagram opposite.

The pancreas serves TWO FUNCTIONS which are carried out by two different

groups of cells within the organ. These two groups of cells are designated

as the

exocrine

and the endocrine portions of the pancreas. If a cell is exocrine it does

not secrete it's products into the bloodstream. If a cell is endocrine, it

does.

In the context of insulin and glucagon, we only need to concern ourselves

with the endocrine pancreas. This is what we will now go on to look at.

Anatomical location of the pancreas

The Endocrine Pancreas

The endocrine pancreas consists of groups of cells known as the islets of

Langerhans which are embedded in the exocrine portion of the gland as

illustrated

in the diagram below.

A schematic illustration of a cross section of the pancreas showing the

relationship of the islets (endocrine cells) to the exocrine cells.

The islets of Langerhans only make up about 1-2% of the total pancreas cells

although the average human pancreas has about one million of them.

It is from these islets that the hormones insulin and glucagon are secreted.

A Delta cell is a cell that secretes somatostatin.

As you can see from the diagram opposite, each islet is richly supplied with

blood vessels. Insulin and glucagon are secreted out of the islet cells

directly

into these blood vessels from where they can travel to all parts of the

body. This is why the islets are called endocrine cells.

Islets are composed of four major cell types. Each one synthesises and

secretes a different hormone although we only need to concern ourselves with

two

of them. These are the alpha and the beta cells.

Cells of the Islets of Langerhans

Remember............

ALPHA cells synthesise and secrete GLUCAGON

BETA cells synthesise and secrete INSULIN

Metabolism

The Metabolic Effects of Insulin and Glucagon

Even while at rest or sleeping, the body is continually using energy to

drive the vital processes that keep us alive. Physical activity increases

energy

requirements above those in the basal (resting) state.

However, although energy use is continuous, the intake of energy in the form

of food is intermittent. Thus, excess fuels taken in with a meal must be

stored

for subsequent use in between meals. Insulin and glucagon are the primary

hormones that coordinate and regulate the storage and release of the body's

fuel.

The Metabolic Effects of Insulin

Insulin is a polypeptide hormone that travels around the bloodstream. Most

of the cells in the body carry

receptors

for the molecule in their cell membranes. Once the hormone has become bound

to one of these receptors, the receptor gives a signal to the cell's

interior.

This signal leads to many enzyme controlled reactions which, in turn lead to

changes in the metabolism of the cell.

Many of the effects of insulin depend on the particular cell type in which

it stimulates. However, in nearly all of the cells that have insulin

receptors

in their cell membrane, the binding of insulin to the receptors leads to

increased glucose uptake of the cell.

The two types of cells that are the main exceptions are the brain and the

liver. However, this is only due to the fact that these cells are readily

permeable

to glucose, even in the absence of insulin. Liver cell membranes do contain

insulin and glucagon receptors, but binding of the hormone to them affects

cellular processes other than glucose permeability.

The animation below illustrates the way insulin brings about the increase in

glucose uptake.

Glucose enters the cells of the body through glucose transporter (GLUT)

proteins which are embedded within the cell membrane. This is a process

called facilitated

diffusion.

When insulin binds to it's receptor, the intracellular domain of the

receptor

changes shape slightly.

This sets off a chain of reactions. These reactions serve to activate

certain enzymes.

As a result, more glucose transporter proteins are released from

intracellular stores and move to the plasma membrane and become embedded

within it.

What do you think will be the effect of increased numbers of glucose

transporter proteins within the plasma membrane?

Less glucose will enter the blood via facilitated diffusion.

More glucose will enter the blood via facilitated diffusion.

The rate of glucose uptake by facilitated diffusion will increase.

The rate of glucose uptake via facilitated diffusion will decrease.

That's not all. You may be wondering what happens to the all this glucose

that is now entering the cells.

Another of the actions of insulin is to stimulate the rate at which glucose

is used up in cellular respiration. This occurs due to the fact that insulin

stimulates the activity of the some of the enzymes which carry out

glycolysis.

The most important body tissues in terms of insulin (and glucagon) action

are:

List of 3 items

1. The liver

2. The muscle

3. Adipose tissue (fat storage tissue)

list end

Below is a summary of the way insulin influences the physiological processes

within the cells of each of these tissues. The most important ones are

emphasised

by the pointing fingers.

A

indicates that the process stated is stimulated within the cells of that

tissue by the hormone.

Table with 8 columns and 11 rows

Liver

Muscle

Adipose

Stimulation of glucose uptake

Stimulation of cellular respiration

Stimulation of

glycogenesis

Inhibition of

glycogenolysis

Stimulation of amino acid uptake

Stimulation of protein synthesis

Inhibition of protein degradation

Stimulation of

fatty acid and triglyceride synthesis

Inhibition of lipolysis

Stimulation of lipoproteins uptake

table end

Take a look at the

metabolic map

which summarises nutrient flow after a meal.

The Metabolic Effects of Glucagon

Like insulin, glucagon is a polypeptide hormone. However, in contrast to

insulin, receptors for glucagon are not as abundant in cells throughout the

body.

The action of glucagon to increase blood glucose concentrations is largely

as a result of the effects it has on cells of the liver after binding to

membrane

receptors.

Table with 8 columns and 7 rows

The Liver

Muscle

Adipose

Stimulation of glycogenolysis

Inhibition of glycogenesis

Stimulation of

gluconeogenesis

Stimulation of lipolysis

Stimulation of

ketone formation

Stimulation of amino acid uptake

Factors Affecting the Secretion of Insulin and Glucagon

So now we know which cells secrete which of the two hormones. We will now

look at the stimuli for their secretion into the blood.

As you no doubt already know, one of the most important roles of insulin and

glucagon is to maintain constant levels of glucose in the blood and that

they

are secreted in response to fluctuations in blood glucose either side of

this

normal concentration.

The two hormones can do this because they act antagonistically to each

other. This means that they have opposite effects in terms of which way they

cause

blood glucose concentration to be driven after their secretion.

Insulin is secreted from the beta cells of the islets of Langerhans in

response to an increase in blood glucose levels. Therefore, what effect

would you

expect insulin to have on blood glucose concentration?

Insulin will have the following effect on blood glucose concentrations:

An increase.

No change.

A decrease.

Because glucagon acts antagonistically to insulin, this hormone serves to

increase blood glucose levels. Therefore, what do you think is the primary

stimulus

for it's secretion?

a decrease in blood glucose concentration below normal levels.

an increase in blood glucose concentration above normal levels.

However the situation is not as straight forward as it may seem. The

concentration of blood glucose is the most important physiological stimulus,

but there

are several other factors that influence secretion and indeed the inhibition

of insulin and glucagon. If you are studying beyond A Level it would be

helpful

to you if you were

familiar with these.

The Secretion of Insulin in Response to an Increased Blood Glucose

Concentration.

Take a look at the animation below. It will keep running for as long as you

stay on this page. It illustrates the way in which plasma concentrations of

glucose and insulin, in a normal adult, change following an oral glucose

load. This was in the form of 50g of glucose dissolved in water and was

given

following an overnight fast. The levels seen prior to administration of

glucose represent the basal plasma (blood) concentrations of the two

substances.

They are not on the same scale but that doesn't matter.

The main points to notice are:

List of 3 items

1. The concentration of glucose in the blood rises rapidly after the

ingestion of glucose (or a high carbohydrate meal).

Table with 3 columns and 2 rows

This shows that glucose is rapidly absorbed from the gut into the blood.

table end

2. The increase in blood glucose concentration is closely followed in time

by an increase in plasma insulin concentration.

Table with 3 columns and 2 rows

This shows that the beta cells are very sensitive to slight changes in blood

glucose and are capable of responding rapidly.

table end

3. Peak glucose concentration occurs within the first hour and a return to

basal levels within two hours.

This highlights the speed with which insulin brings about the metabolic

changes that serve to remove glucose from the blood.

list end

How do the beta cells know when to stop secreting insulin?

As insulin carries out it's function and starts to bring blood glucose

concentrations back down to normal, then this removes the stimulus that

tells the

beta cells to secrete the insulin in the first place . As a result the beta

cells become less and less stimulated and so the rate of secretion of

insulin

declines in parallel to the rate of decline in blood glucose concentration.

This is an example of

negative feedback.

Ok, so we've had a look at how insulin is secreted in response to elevated

blood glucose levels. However, one thing that is easily forgotten is the

fact

that something else is happening at the same time. That is that while

insulin secretion is being stimulated, glucagon secretion is being

inhibited.

After a high carbohydrate meal, the ratio of insulin:glucagon concentrations

can reach 10:1.

Take a look at the next graph, it is the same as the first but with glucagon

concentration added. The key things to notice are:

List of 3 items

1. The initial increase in glucagon concentration parallels the increase in

glucose.

Table with 3 columns and 2 rows

This is due to stimulation of the alpha cells by nerve impulses triggered by

the presence of " food " in the gut.

table end

2. The glucagon concentration begins to fall shortly after glucose

concentration begins to rise.

Table with 4 columns and 2 rows

The alpha cells detect that glucose concentrations are rising above normal

levels. This change starts processes within the cells that inhibit the

secretion

of glucagon.

table end

3. After blood glucose and insulin levels return to normal, the

concentration of glucagon begins to increase again back towards basal

levels.

list end

Here's another easy question:

Can you figure out why the glucagon levels start to rise again at the point

in which they do?

If you want to look at a still image of the graph,

click here.

Because the glucagon concentration has fallen to its lowest possible level

and can't decrease any further.

Because the glucose concentration has reached its peak.

Because the inhibition of glucagon secretion has been removed.

The secretion of glucagon in response to a decrease in blood glucose

concentration.

In direct contrast to insulin, a decrease in blood glucose concentration

stimulates glucagon secretion.Therefore, circulating levels of glucagon tend

to

be highest during periods of starvation (fasting)or prolonged exercise (e.g.

running a marathon). During these times, blood glucose concentrations are

at their lowest. The ratio of insulin:glucagon concentrations is

approximately 1:2.

Man Exercising

The glucagon brings about changes in the body's metabolism that raise blood

glucose concentration back to normal. The alpha cells detect that glucose

concentrations

are returning to normal and stop secreting glucagon. Again, this is an

example of negative feedback control.

Summary

So, as you can see, the pattern of insulin and glucagon secretion is an

example of one of the body's control processes whereby the " steady state "

blood

glucose concentration is maintained. This is achieved by means of a delicate

balance between two hormones that have opposite effects. The whole thing is

controlled by a negative feedback system.

Take a look at the

diagram

summarising the whole process.

But what exactly are these effects? What effects do the hormones have on the

body's metabolism that cause the blood glucose levels to be returned to

normal?

These are the questions addressed in the next section.

An Overview of Diabetes

Diabetes Mellitus

OVERVIEW

FACTS AND FIGURES

WHAT CAUSES DIABETES?

COMPLICATIONS OF DIABETES

MANAGING DIABETES

LINKS

Overview

Diabetes mellitus is a disease that arises as a result of insufficient

insulin being produced by the beta cells, or the insulin that is produced

does not

function properly.

There are two main types of diabetes:

List of 1 items

1. Insulin-dependent diabetes (also known as Type 1 diabetes or juvenile

diabetes)

list end

List of 1 items

2. Non-insulin-dependent diabetes (also known as Type 2 diabetes or maturity

onset diabetes)

list end

The common characteristic of both types of diabetes is an abnormally high

blood glucose concentration.

The table below summarises some of the main characteristics of each form of

the disease.

Table with 2 columns and 16 rows

Insulin Dependent Non Insulin Dependent

Diabetes Diabetes

(Type 1) (Type

2)

Severe lack of insulin due to the The beta cells do not

produce

destruction of beta cells. sufficient

insulin or the insulin that

is produced becomes less effective.

Develops rapidly over time. Develops more

gradually over time.

Usually appears before the age of 35 Usually appears in people

over the

and most often between 10 and 16 age of 40 (hence maturity

onset

years of age (hence juvenile diabetes). diabetes).

Accounts for about 10% of all Accounts for about 90%

of all

diabetics.

diabetics.

table end

A Few Facts and Figures

List of 1 items

.. In the U.K. an estimated 1.4 million people are known to have diabetes

with possibly up to a million more undiagnosed.

list end

List of 1 items

.. Diabetes is the fourth leading cause of death in the most developed

countries.

list end

List of 1 items

.. It is projected that between 1995 and 2025, the number of the worldwide

adult population affected by diabetes mellitus will increase by 122%

This is mainly due to population ageing and growth, increasing incidence of

obesity, increases in diets high in saturated fats and people tending to

lead

lifestyles that lack regular exercise.

list end

What causes diabetes?

Type 1 diabetes

In type 1 diabetes, the beta cells are destroyed by an autoimmune process

whereby the body's immune system recognises the cells as " foreign " rather

than

" self " and therefore attacks them.

The cause of the autoimmune disorder is currently subject to much research.

At least two major components are though to contribute to the disease

appearring.

The first is a genetic component by which certain individuals, with defects

in certain genes, have an increased susceptibility. So far, two genes have

been identified that appear to put an individual at risk, but there are

certain to be others involved. The genetic component is not, in itself,

sufficient

to cause the autoimmunity. The effects of an as yet unidentified

environmental component are required to produce the disease in these

suceptible individuals.

Viruses have been suggested as likely candidates.

Type 2 diabetes

The cause of type 2 diabetes is thought to be due to both defects in the

beta cells (so that less insulin is produced) and also to the decrease in

insulin's

ability to stimulate the uptake of glucose in tissues (a condition referred

to as

insulin resistance).

The cause of this insulin resistence is not fully known although it has been

linked to defects in the action of insulin after it has bound to the

receptor

on the surface of cells (i.e. the cascade of reactions that were mentioned

earlier).

In many cases, patients with this form of the disease are obese but the

exact link between the two remains unclear.

As in type 1 diabetes, there is a genetic influence. In fact, type 2

diabetes tends to run in families even more strongly than type 1. There is

nearly a

100% chance that if one genetically identical twin develops type 2 diabetes,

the other will also, even if they are raised in completely different

environments.

Diabetes Mellitus Can Result in both Short and Long-Term Complications

Diabetes mellitus is a disease that has traditionally been studied at great

length by scientists in an attempt to make it easier for those sufferring

from

the disease to keep their blood glucose levels under control. Such intensive

research has meant that diabetics are able to lead relatively normal

lifestyles

provided they adopt a responsible approach in the management of the

condition. If the correct approach is achieved and maintained, then the risk

of developing

diabetic complications is minimised greatly. The section below outlines the

mechanisms by which these complications arise if blood glucose levels are

not

controlled.

Short-Term, Acute Complications

In the absence of either insulin secretion or insulin action, the blood

glucose concentation

rises quickly

and steeply (hyperglycaemia) after glucose or carbohydrate intake. As a

result, the amount of glucose that gets filtered into the kidney tubules

increases

also. The capacity for the kidney to reabsorb glucose from the urine is

limited. If the amount of glucose that enters the tubules is too high, (i.e.

if

it exceeds the glucose threshold), glucose appears in the urine. This

condition is termed glucosuria. Because of osmotic effects, glucose in the

urine

draws with it considerable amounts of water, which will be excreted along

with the glucose. As a result, urine volume and frequency increases

(polyuria)

and the diabetic individual is frequently dehydrated and is nearly always

thirsty

(polydipsia).

In type 1 diabetics, the unopposed actions of glucagon result in increased

ketone formation by the liver. These ketones are acidic and their build up

considerably

lowers blood pH and disturbs the acid/base balance of the body. This

condition is termed ketoacidosis and is the largest cause of death amongst

diabetics

under the age of 30. As with glucose, if ketones reach high enough

concentrations in the blood, they will begin to appear in the urine. Ketones

carry cations,

such as sodium (Na+) and potassium (K+), with them into the urine leading to

electrolye imbalances in the body.

Consequences of these complications may include abdominal pain, vomiting,

sweet-smelling breath and severe dehydration. Severe cases can lead to

diabetic

coma and death.

Long-Term, Chronic Complications

Several secondary complications usually accompany long-standing diabetes

mellitus. These often involve gradual changes that develop over a period of

years

and may shorten the life expectancy of diabetic individuals. The most common

involve the vascular system. Changes much like those seen in atherosclerosis

lead to narrowing of the arteries supplying the brain, heart and lower

limbs. This increases susceptibility to strokes, heart attack and amputation

of

the limbs.

Impairment to the vascular system is thought to be the reason behind

conditions such as:

Table with 3 columns and 8 rows

Retinopathy

Lesions in the small blood vessels and capillaries supplying the retina of

the eye.

Every year thousands of diabetics become blind as a result.

Neuropathy

Impairment of the function of the autonomic nerves.

Leads to abnormalities in the function of the gastrointestinal tract and

bladder and also loss of feeling in lower extremities.

Nephropathy

Lesions in the small blood vessels and capillaries supplying the kidney.

Can lead to kidney disease.

table end

If hypoglycaemia is prolonged, this can lead to the condition known as

glucose toxicity whereby cellular proteins, such as ion channels, receptors

etc.,

become glycosylated (polysaccharide side chains added to them) and their

function impaired.

As mentioned, the likelihood of such conditions as these developing, is

greatly dependent on the long-term control of blood glucose levels by the

patient.

Good control throughout life is highly effective in minimising this risk.

The section below outlines the ways in which the control of blood glucose in

diabetics can be achieved.

Managing Diabetes

If you had lived before the turn of the 20th century and developed diabetes

mellitus, you would have faced the prospect of increasing lethargy, gradual

loss of weight and certain premature death. Historically, " treatments "

included excessive feeding of sugar, a diet consisting almost exclusively of

potatoes

and also, for some reason, bleeding!!

For diabetic individuals, the adherence to a " sensible " diet is crucial. It

needs to be low in sugar in order to help prevent blood glucose levels

becoming,

and staying too high. It also needs to be low in fat but high in complex

carbohydrates such as bread, pasta, potatoes etc. These take a long time to

digest

and so elicit a relatively slow increase in blood glucose.

For type 1 diabetics, the constant monitoring of their blood glucose levels

is required. Methods include the use of biochemical test strips which are

impregnated

with a reagent that changes colour after a drop of blood is placed onto it.

The shade of the colour is compared to a standard colour chart to determine

the amount of glucose present in the blood. More technical equipment such as

electronic hand held meters contain electrodes. Once a drop of blood is

placed

onto the electrode, it generates a readout of the glucose concentration.

Type 1 diabetics are requred to inject themselves with insulin at mealtimes

and other intervals throughout the day to keep blood glucose levels under

the

best possible control. Convenient " pocket pens " allow injection of a set

amount of insulin without the need to fill syringes from a separate insulin

container

prior to injection. Portable insulin pumps were one of the first new

technologies to be introduced into diabetes care. A small pump containing

the reservoir

of insulin is worn around the waist. A fine catheter delivers a controlled

infusion of insulin into the tissue under the skin with patient-activated

boosts

at mealtimes.

A major problem that presents itself to type 1 diabetics lies in the risk of

injecting too much insulin, taking too much exercise or too little food, or

a combination of these factors. In these cases, blood glucose levels drop

too low and, if unchecked, will lead to hypoglycaemia. The threshold for

hypoglycaemia

is approximately 3mM glucose, at which point the majority of diabetics sense

the onset of a " hypo. " During a hypo, the individual initially develops a

headache and nausea. The full consequences are distressing; behaviour

becomes increasingly erratic and bizzare leading to convulsions,

unconciousness followed

by coma and death due to lack of glucose to the brain (the brain can't use

any other fuel source).

Which of these two remedies would you suggest for severe hypoglycaemia?

Injection of insulin and glucose tablets.

The injection of both insulin and glucagon.

Glucose tablets and the injection of glucagon.

The injection of glucagon and vigourous exercise.

The managment of type 2 diabetes can often be achieved through the adherence

to a strict diet alone. If this isn't the case, it is achieved through the

combination of diet and hypoglycaemic drugs such as:

List of 1 items

.. Sulfonylureas: stimulate insulin secretion from the beta cells of the

islets.

list end

List of 1 items

.. Biguanides: have actions similar to those of insulin.

list end

List of 1 items

.. Alpha-glucosidase inhibitors: inhibit alpha-glucosidase, an enzyme

responsible for starch and sucrose digestion in the gut.

list end

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

ya, often times after exercising your sugars may be higher. I cannot recall why

that is, was told why 2 years ago. I think it is that your body breaks down

carbs quicker or puts out some natural sugar for energy or some such thing.

Sorry I don't have the exact answer.

Regards,

Questions looking for answers

What causes this?

First, I will note the following observation regarding my glucose level

reading and exercise:

Prior to exercising for an hour and fifteen minutes, which includes walking

approximately 1.9 miles and several sets of isometric exercises,

a glucose of 120 or less yields a post exercise glucose reading of 160 plus

or minus 10 points, and I feel exhausted for a long time.

If I have a pre-exercise glucose level reading of 150 to 160, my post

exercise glucose level reading is usually around 75 plus or minus 10 points,

and I feel fairly good.

Do others experience this?

What are the explanations for these observations? Post this message to

other forums if you wish. I would really like to know.

[Guest guest]

Pat I cannot recall, how do you exercise without geting your sugar to go high?

Regards,

Questions looking for answers

What causes this?

First, I will note the following observation regarding my glucose level

reading and exercise:

Prior to exercising for an hour and fifteen minutes, which includes walking

approximately 1.9 miles and several sets of isometric exercises,

a glucose of 120 or less yields a post exercise glucose reading of 160 plus

or minus 10 points, and I feel exhausted for a long time.

If I have a pre-exercise glucose level reading of 150 to 160, my post

exercise glucose level reading is usually around 75 plus or minus 10 points,

and I feel fairly good.

Do others experience this?

What are the explanations for these observations? Post this message to

other forums if you wish. I would really like to know.

[Guest guest]

Ok I am confused I thought if you had a high reading that doing some excise

would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

Ok I am confused I thought if you had a high reading that doing some excise

would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

Ok I am confused I thought if you had a high reading that doing some excise

would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

No, it means that 1. if your blood sugar is over 250, you should not

exercise at all until it goes down as exeercise wil make it rise even

higher. this is because your body is not using glucose correctly and will

actually put out more glucogon fro the liver when you exercise whithBG that

high.

2. If you exercise with a blood sugar that is rather low, then your body

puts out too much glucogon as it is trying to raise up your sugar to a more

normal level; but it puts out too much.

3. If you exercise with a BG of say 120 then your body does not put out more

glucogon.

It's a balancing act!

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some excise

would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

No, it means that 1. if your blood sugar is over 250, you should not

exercise at all until it goes down as exeercise wil make it rise even

higher. this is because your body is not using glucose correctly and will

actually put out more glucogon fro the liver when you exercise whithBG that

high.

2. If you exercise with a blood sugar that is rather low, then your body

puts out too much glucogon as it is trying to raise up your sugar to a more

normal level; but it puts out too much.

3. If you exercise with a BG of say 120 then your body does not put out more

glucogon.

It's a balancing act!

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some excise

would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

No, it means that 1. if your blood sugar is over 250, you should not

exercise at all until it goes down as exeercise wil make it rise even

higher. this is because your body is not using glucose correctly and will

actually put out more glucogon fro the liver when you exercise whithBG that

high.

2. If you exercise with a blood sugar that is rather low, then your body

puts out too much glucogon as it is trying to raise up your sugar to a more

normal level; but it puts out too much.

3. If you exercise with a BG of say 120 then your body does not put out more

glucogon.

It's a balancing act!

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some excise

would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

yes, this is a very complicated article! but thanks, anyway.

Re: Questions looking for answers

Thanks for your response, which prompted me to do more research on

the internet. I found the following, which is a good primmer on metabolism

and diabetes in normal people. I like your simple explanation much better

than the one presented below:

The Pancreas

The topic of insulin and glucagon begins here, in the pancreas.The pancreas

is located in the abdominal cavity adjacent to the upper part of the small

intestine

as shown in the diagram opposite.

The pancreas serves TWO FUNCTIONS which are carried out by two different

groups of cells within the organ. These two groups of cells are designated

as the

exocrine

and the endocrine portions of the pancreas. If a cell is exocrine it does

not secrete it's products into the bloodstream. If a cell is endocrine, it

does.

In the context of insulin and glucagon, we only need to concern ourselves

with the endocrine pancreas. This is what we will now go on to look at.

Anatomical location of the pancreas

The Endocrine Pancreas

The endocrine pancreas consists of groups of cells known as the islets of

Langerhans which are embedded in the exocrine portion of the gland as

illustrated

in the diagram below.

A schematic illustration of a cross section of the pancreas showing the

relationship of the islets (endocrine cells) to the exocrine cells.

The islets of Langerhans only make up about 1-2% of the total pancreas cells

although the average human pancreas has about one million of them.

It is from these islets that the hormones insulin and glucagon are secreted.

A Delta cell is a cell that secretes somatostatin.

As you can see from the diagram opposite, each islet is richly supplied with

blood vessels. Insulin and glucagon are secreted out of the islet cells

directly

into these blood vessels from where they can travel to all parts of the

body. This is why the islets are called endocrine cells.

Islets are composed of four major cell types. Each one synthesises and

secretes a different hormone although we only need to concern ourselves with

two

of them. These are the alpha and the beta cells.

Cells of the Islets of Langerhans

Remember............

ALPHA cells synthesise and secrete GLUCAGON

BETA cells synthesise and secrete INSULIN

Metabolism

The Metabolic Effects of Insulin and Glucagon

Even while at rest or sleeping, the body is continually using energy to

drive the vital processes that keep us alive. Physical activity increases

energy

requirements above those in the basal (resting) state.

However, although energy use is continuous, the intake of energy in the form

of food is intermittent. Thus, excess fuels taken in with a meal must be

stored

for subsequent use in between meals. Insulin and glucagon are the primary

hormones that coordinate and regulate the storage and release of the body's

fuel.

The Metabolic Effects of Insulin

Insulin is a polypeptide hormone that travels around the bloodstream. Most

of the cells in the body carry

receptors

for the molecule in their cell membranes. Once the hormone has become bound

to one of these receptors, the receptor gives a signal to the cell's

interior.

This signal leads to many enzyme controlled reactions which, in turn lead to

changes in the metabolism of the cell.

Many of the effects of insulin depend on the particular cell type in which

it stimulates. However, in nearly all of the cells that have insulin

receptors

in their cell membrane, the binding of insulin to the receptors leads to

increased glucose uptake of the cell.

The two types of cells that are the main exceptions are the brain and the

liver. However, this is only due to the fact that these cells are readily

permeable

to glucose, even in the absence of insulin. Liver cell membranes do contain

insulin and glucagon receptors, but binding of the hormone to them affects

cellular processes other than glucose permeability.

The animation below illustrates the way insulin brings about the increase in

glucose uptake.

Glucose enters the cells of the body through glucose transporter (GLUT)

proteins which are embedded within the cell membrane. This is a process

called facilitated

diffusion.

When insulin binds to it's receptor, the intracellular domain of the

receptor

changes shape slightly.

This sets off a chain of reactions. These reactions serve to activate

certain enzymes.

As a result, more glucose transporter proteins are released from

intracellular stores and move to the plasma membrane and become embedded

within it.

What do you think will be the effect of increased numbers of glucose

transporter proteins within the plasma membrane?

Less glucose will enter the blood via facilitated diffusion.

More glucose will enter the blood via facilitated diffusion.

The rate of glucose uptake by facilitated diffusion will increase.

The rate of glucose uptake via facilitated diffusion will decrease.

That's not all. You may be wondering what happens to the all this glucose

that is now entering the cells.

Another of the actions of insulin is to stimulate the rate at which glucose

is used up in cellular respiration. This occurs due to the fact that insulin

stimulates the activity of the some of the enzymes which carry out

glycolysis.

The most important body tissues in terms of insulin (and glucagon) action

are:

List of 3 items

1. The liver

2. The muscle

3. Adipose tissue (fat storage tissue)

list end

Below is a summary of the way insulin influences the physiological processes

within the cells of each of these tissues. The most important ones are

emphasised

by the pointing fingers.

A

indicates that the process stated is stimulated within the cells of that

tissue by the hormone.

Table with 8 columns and 11 rows

Liver

Muscle

Adipose

Stimulation of glucose uptake

Stimulation of cellular respiration

Stimulation of

glycogenesis

Inhibition of

glycogenolysis

Stimulation of amino acid uptake

Stimulation of protein synthesis

Inhibition of protein degradation

Stimulation of

fatty acid and triglyceride synthesis

Inhibition of lipolysis

Stimulation of lipoproteins uptake

table end

Take a look at the

metabolic map

which summarises nutrient flow after a meal.

The Metabolic Effects of Glucagon

Like insulin, glucagon is a polypeptide hormone. However, in contrast to

insulin, receptors for glucagon are not as abundant in cells throughout the

body.

The action of glucagon to increase blood glucose concentrations is largely

as a result of the effects it has on cells of the liver after binding to

membrane

receptors.

Table with 8 columns and 7 rows

The Liver

Muscle

Adipose

Stimulation of glycogenolysis

Inhibition of glycogenesis

Stimulation of

gluconeogenesis

Stimulation of lipolysis

Stimulation of

ketone formation

Stimulation of amino acid uptake

Factors Affecting the Secretion of Insulin and Glucagon

So now we know which cells secrete which of the two hormones. We will now

look at the stimuli for their secretion into the blood.

As you no doubt already know, one of the most important roles of insulin and

glucagon is to maintain constant levels of glucose in the blood and that

they

are secreted in response to fluctuations in blood glucose either side of

this

normal concentration.

The two hormones can do this because they act antagonistically to each

other. This means that they have opposite effects in terms of which way they

cause

blood glucose concentration to be driven after their secretion.

Insulin is secreted from the beta cells of the islets of Langerhans in

response to an increase in blood glucose levels. Therefore, what effect

would you

expect insulin to have on blood glucose concentration?

Insulin will have the following effect on blood glucose concentrations:

An increase.

No change.

A decrease.

Because glucagon acts antagonistically to insulin, this hormone serves to

increase blood glucose levels. Therefore, what do you think is the primary

stimulus

for it's secretion?

a decrease in blood glucose concentration below normal levels.

an increase in blood glucose concentration above normal levels.

However the situation is not as straight forward as it may seem. The

concentration of blood glucose is the most important physiological stimulus,

but there

are several other factors that influence secretion and indeed the inhibition

of insulin and glucagon. If you are studying beyond A Level it would be

helpful

to you if you were

familiar with these.

The Secretion of Insulin in Response to an Increased Blood Glucose

Concentration.

Take a look at the animation below. It will keep running for as long as you

stay on this page. It illustrates the way in which plasma concentrations of

glucose and insulin, in a normal adult, change following an oral glucose

load. This was in the form of 50g of glucose dissolved in water and was

given

following an overnight fast. The levels seen prior to administration of

glucose represent the basal plasma (blood) concentrations of the two

substances.

They are not on the same scale but that doesn't matter.

The main points to notice are:

List of 3 items

1. The concentration of glucose in the blood rises rapidly after the

ingestion of glucose (or a high carbohydrate meal).

Table with 3 columns and 2 rows

This shows that glucose is rapidly absorbed from the gut into the blood.

table end

2. The increase in blood glucose concentration is closely followed in time

by an increase in plasma insulin concentration.

Table with 3 columns and 2 rows

This shows that the beta cells are very sensitive to slight changes in blood

glucose and are capable of responding rapidly.

table end

3. Peak glucose concentration occurs within the first hour and a return to

basal levels within two hours.

This highlights the speed with which insulin brings about the metabolic

changes that serve to remove glucose from the blood.

list end

How do the beta cells know when to stop secreting insulin?

As insulin carries out it's function and starts to bring blood glucose

concentrations back down to normal, then this removes the stimulus that

tells the

beta cells to secrete the insulin in the first place . As a result the beta

cells become less and less stimulated and so the rate of secretion of

insulin

declines in parallel to the rate of decline in blood glucose concentration.

This is an example of

negative feedback.

Ok, so we've had a look at how insulin is secreted in response to elevated

blood glucose levels. However, one thing that is easily forgotten is the

fact

that something else is happening at the same time. That is that while

insulin secretion is being stimulated, glucagon secretion is being

inhibited.

After a high carbohydrate meal, the ratio of insulin:glucagon concentrations

can reach 10:1.

Take a look at the next graph, it is the same as the first but with glucagon

concentration added. The key things to notice are:

List of 3 items

1. The initial increase in glucagon concentration parallels the increase in

glucose.

Table with 3 columns and 2 rows

This is due to stimulation of the alpha cells by nerve impulses triggered by

the presence of " food " in the gut.

table end

2. The glucagon concentration begins to fall shortly after glucose

concentration begins to rise.

Table with 4 columns and 2 rows

The alpha cells detect that glucose concentrations are rising above normal

levels. This change starts processes within the cells that inhibit the

secretion

of glucagon.

table end

3. After blood glucose and insulin levels return to normal, the

concentration of glucagon begins to increase again back towards basal

levels.

list end

Here's another easy question:

Can you figure out why the glucagon levels start to rise again at the point

in which they do?

If you want to look at a still image of the graph,

click here.

Because the glucagon concentration has fallen to its lowest possible level

and can't decrease any further.

Because the glucose concentration has reached its peak.

Because the inhibition of glucagon secretion has been removed.

The secretion of glucagon in response to a decrease in blood glucose

concentration.

In direct contrast to insulin, a decrease in blood glucose concentration

stimulates glucagon secretion.Therefore, circulating levels of glucagon tend

to

be highest during periods of starvation (fasting)or prolonged exercise (e.g.

running a marathon). During these times, blood glucose concentrations are

at their lowest. The ratio of insulin:glucagon concentrations is

approximately 1:2.

Man Exercising

The glucagon brings about changes in the body's metabolism that raise blood

glucose concentration back to normal. The alpha cells detect that glucose

concentrations

are returning to normal and stop secreting glucagon. Again, this is an

example of negative feedback control.

Summary

So, as you can see, the pattern of insulin and glucagon secretion is an

example of one of the body's control processes whereby the " steady state "

blood

glucose concentration is maintained. This is achieved by means of a delicate

balance between two hormones that have opposite effects. The whole thing is

controlled by a negative feedback system.

Take a look at the

diagram

summarising the whole process.

But what exactly are these effects? What effects do the hormones have on the

body's metabolism that cause the blood glucose levels to be returned to

normal?

These are the questions addressed in the next section.

An Overview of Diabetes

Diabetes Mellitus

OVERVIEW

FACTS AND FIGURES

WHAT CAUSES DIABETES?

COMPLICATIONS OF DIABETES

MANAGING DIABETES

LINKS

Overview

Diabetes mellitus is a disease that arises as a result of insufficient

insulin being produced by the beta cells, or the insulin that is produced

does not

function properly.

There are two main types of diabetes:

List of 1 items

1. Insulin-dependent diabetes (also known as Type 1 diabetes or juvenile

diabetes)

list end

List of 1 items

2. Non-insulin-dependent diabetes (also known as Type 2 diabetes or maturity

onset diabetes)

list end

The common characteristic of both types of diabetes is an abnormally high

blood glucose concentration.

The table below summarises some of the main characteristics of each form of

the disease.

Table with 2 columns and 16 rows

Insulin Dependent Non Insulin Dependent

Diabetes Diabetes

(Type 1) (Type

2)

Severe lack of insulin due to the The beta cells do not

produce

destruction of beta cells. sufficient

insulin or the insulin that

is produced becomes less effective.

Develops rapidly over time. Develops more

gradually over time.

Usually appears before the age of 35 Usually appears in people

over the

and most often between 10 and 16 age of 40 (hence maturity

onset

years of age (hence juvenile diabetes). diabetes).

Accounts for about 10% of all Accounts for about 90%

of all

diabetics.

diabetics.

table end

A Few Facts and Figures

List of 1 items

.. In the U.K. an estimated 1.4 million people are known to have diabetes

with possibly up to a million more undiagnosed.

list end

List of 1 items

.. Diabetes is the fourth leading cause of death in the most developed

countries.

list end

List of 1 items

.. It is projected that between 1995 and 2025, the number of the worldwide

adult population affected by diabetes mellitus will increase by 122%

This is mainly due to population ageing and growth, increasing incidence of

obesity, increases in diets high in saturated fats and people tending to

lead

lifestyles that lack regular exercise.

list end

What causes diabetes?

Type 1 diabetes

In type 1 diabetes, the beta cells are destroyed by an autoimmune process

whereby the body's immune system recognises the cells as " foreign " rather

than

" self " and therefore attacks them.

The cause of the autoimmune disorder is currently subject to much research.

At least two major components are though to contribute to the disease

appearring.

The first is a genetic component by which certain individuals, with defects

in certain genes, have an increased susceptibility. So far, two genes have

been identified that appear to put an individual at risk, but there are

certain to be others involved. The genetic component is not, in itself,

sufficient

to cause the autoimmunity. The effects of an as yet unidentified

environmental component are required to produce the disease in these

suceptible individuals.

Viruses have been suggested as likely candidates.

Type 2 diabetes

The cause of type 2 diabetes is thought to be due to both defects in the

beta cells (so that less insulin is produced) and also to the decrease in

insulin's

ability to stimulate the uptake of glucose in tissues (a condition referred

to as

insulin resistance).

The cause of this insulin resistence is not fully known although it has been

linked to defects in the action of insulin after it has bound to the

receptor

on the surface of cells (i.e. the cascade of reactions that were mentioned

earlier).

In many cases, patients with this form of the disease are obese but the

exact link between the two remains unclear.

As in type 1 diabetes, there is a genetic influence. In fact, type 2

diabetes tends to run in families even more strongly than type 1. There is

nearly a

100% chance that if one genetically identical twin develops type 2 diabetes,

the other will also, even if they are raised in completely different

environments.

Diabetes Mellitus Can Result in both Short and Long-Term Complications

Diabetes mellitus is a disease that has traditionally been studied at great

length by scientists in an attempt to make it easier for those sufferring

from

the disease to keep their blood glucose levels under control. Such intensive

research has meant that diabetics are able to lead relatively normal

lifestyles

provided they adopt a responsible approach in the management of the

condition. If the correct approach is achieved and maintained, then the risk

of developing

diabetic complications is minimised greatly. The section below outlines the

mechanisms by which these complications arise if blood glucose levels are

not

controlled.

Short-Term, Acute Complications

In the absence of either insulin secretion or insulin action, the blood

glucose concentation

rises quickly

and steeply (hyperglycaemia) after glucose or carbohydrate intake. As a

result, the amount of glucose that gets filtered into the kidney tubules

increases

also. The capacity for the kidney to reabsorb glucose from the urine is

limited. If the amount of glucose that enters the tubules is too high, (i.e.

if

it exceeds the glucose threshold), glucose appears in the urine. This

condition is termed glucosuria. Because of osmotic effects, glucose in the

urine

draws with it considerable amounts of water, which will be excreted along

with the glucose. As a result, urine volume and frequency increases

(polyuria)

and the diabetic individual is frequently dehydrated and is nearly always

thirsty

(polydipsia).

In type 1 diabetics, the unopposed actions of glucagon result in increased

ketone formation by the liver. These ketones are acidic and their build up

considerably

lowers blood pH and disturbs the acid/base balance of the body. This

condition is termed ketoacidosis and is the largest cause of death amongst

diabetics

under the age of 30. As with glucose, if ketones reach high enough

concentrations in the blood, they will begin to appear in the urine. Ketones

carry cations,

such as sodium (Na+) and potassium (K+), with them into the urine leading to

electrolye imbalances in the body.

Consequences of these complications may include abdominal pain, vomiting,

sweet-smelling breath and severe dehydration. Severe cases can lead to

diabetic

coma and death.

Long-Term, Chronic Complications

Several secondary complications usually accompany long-standing diabetes

mellitus. These often involve gradual changes that develop over a period of

years

and may shorten the life expectancy of diabetic individuals. The most common

involve the vascular system. Changes much like those seen in atherosclerosis

lead to narrowing of the arteries supplying the brain, heart and lower

limbs. This increases susceptibility to strokes, heart attack and amputation

of

the limbs.

Impairment to the vascular system is thought to be the reason behind

conditions such as:

Table with 3 columns and 8 rows

Retinopathy

Lesions in the small blood vessels and capillaries supplying the retina of

the eye.

Every year thousands of diabetics become blind as a result.

Neuropathy

Impairment of the function of the autonomic nerves.

Leads to abnormalities in the function of the gastrointestinal tract and

bladder and also loss of feeling in lower extremities.

Nephropathy

Lesions in the small blood vessels and capillaries supplying the kidney.

Can lead to kidney disease.

table end

If hypoglycaemia is prolonged, this can lead to the condition known as

glucose toxicity whereby cellular proteins, such as ion channels, receptors

etc.,

become glycosylated (polysaccharide side chains added to them) and their

function impaired.

As mentioned, the likelihood of such conditions as these developing, is

greatly dependent on the long-term control of blood glucose levels by the

patient.

Good control throughout life is highly effective in minimising this risk.

The section below outlines the ways in which the control of blood glucose in

diabetics can be achieved.

Managing Diabetes

If you had lived before the turn of the 20th century and developed diabetes

mellitus, you would have faced the prospect of increasing lethargy, gradual

loss of weight and certain premature death. Historically, " treatments "

included excessive feeding of sugar, a diet consisting almost exclusively of

potatoes

and also, for some reason, bleeding!!

For diabetic individuals, the adherence to a " sensible " diet is crucial. It

needs to be low in sugar in order to help prevent blood glucose levels

becoming,

and staying too high. It also needs to be low in fat but high in complex

carbohydrates such as bread, pasta, potatoes etc. These take a long time to

digest

and so elicit a relatively slow increase in blood glucose.

For type 1 diabetics, the constant monitoring of their blood glucose levels

is required. Methods include the use of biochemical test strips which are

impregnated

with a reagent that changes colour after a drop of blood is placed onto it.

The shade of the colour is compared to a standard colour chart to determine

the amount of glucose present in the blood. More technical equipment such as

electronic hand held meters contain electrodes. Once a drop of blood is

placed

onto the electrode, it generates a readout of the glucose concentration.

Type 1 diabetics are requred to inject themselves with insulin at mealtimes

and other intervals throughout the day to keep blood glucose levels under

the

best possible control. Convenient " pocket pens " allow injection of a set

amount of insulin without the need to fill syringes from a separate insulin

container

prior to injection. Portable insulin pumps were one of the first new

technologies to be introduced into diabetes care. A small pump containing

the reservoir

of insulin is worn around the waist. A fine catheter delivers a controlled

infusion of insulin into the tissue under the skin with patient-activated

boosts

at mealtimes.

A major problem that presents itself to type 1 diabetics lies in the risk of

injecting too much insulin, taking too much exercise or too little food, or

a combination of these factors. In these cases, blood glucose levels drop

too low and, if unchecked, will lead to hypoglycaemia. The threshold for

hypoglycaemia

is approximately 3mM glucose, at which point the majority of diabetics sense

the onset of a " hypo. " During a hypo, the individual initially develops a

headache and nausea. The full consequences are distressing; behaviour

becomes increasingly erratic and bizzare leading to convulsions,

unconciousness followed

by coma and death due to lack of glucose to the brain (the brain can't use

any other fuel source).

Which of these two remedies would you suggest for severe hypoglycaemia?

Injection of insulin and glucose tablets.

The injection of both insulin and glucagon.

Glucose tablets and the injection of glucagon.

The injection of glucagon and vigourous exercise.

The managment of type 2 diabetes can often be achieved through the adherence

to a strict diet alone. If this isn't the case, it is achieved through the

combination of diet and hypoglycaemic drugs such as:

List of 1 items

.. Sulfonylureas: stimulate insulin secretion from the beta cells of the

islets.

list end

List of 1 items

.. Biguanides: have actions similar to those of insulin.

list end

List of 1 items

.. Alpha-glucosidase inhibitors: inhibit alpha-glucosidase, an enzyme

responsible for starch and sucrose digestion in the gut.

list end

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

yes, this is a very complicated article! but thanks, anyway.

Re: Questions looking for answers

Thanks for your response, which prompted me to do more research on

the internet. I found the following, which is a good primmer on metabolism

and diabetes in normal people. I like your simple explanation much better

than the one presented below:

The Pancreas

The topic of insulin and glucagon begins here, in the pancreas.The pancreas

is located in the abdominal cavity adjacent to the upper part of the small

intestine

as shown in the diagram opposite.

The pancreas serves TWO FUNCTIONS which are carried out by two different

groups of cells within the organ. These two groups of cells are designated

as the

exocrine

and the endocrine portions of the pancreas. If a cell is exocrine it does

not secrete it's products into the bloodstream. If a cell is endocrine, it

does.

In the context of insulin and glucagon, we only need to concern ourselves

with the endocrine pancreas. This is what we will now go on to look at.

Anatomical location of the pancreas

The Endocrine Pancreas

The endocrine pancreas consists of groups of cells known as the islets of

Langerhans which are embedded in the exocrine portion of the gland as

illustrated

in the diagram below.

A schematic illustration of a cross section of the pancreas showing the

relationship of the islets (endocrine cells) to the exocrine cells.

The islets of Langerhans only make up about 1-2% of the total pancreas cells

although the average human pancreas has about one million of them.

It is from these islets that the hormones insulin and glucagon are secreted.

A Delta cell is a cell that secretes somatostatin.

As you can see from the diagram opposite, each islet is richly supplied with

blood vessels. Insulin and glucagon are secreted out of the islet cells

directly

into these blood vessels from where they can travel to all parts of the

body. This is why the islets are called endocrine cells.

Islets are composed of four major cell types. Each one synthesises and

secretes a different hormone although we only need to concern ourselves with

two

of them. These are the alpha and the beta cells.

Cells of the Islets of Langerhans

Remember............

ALPHA cells synthesise and secrete GLUCAGON

BETA cells synthesise and secrete INSULIN

Metabolism

The Metabolic Effects of Insulin and Glucagon

Even while at rest or sleeping, the body is continually using energy to

drive the vital processes that keep us alive. Physical activity increases

energy

requirements above those in the basal (resting) state.

However, although energy use is continuous, the intake of energy in the form

of food is intermittent. Thus, excess fuels taken in with a meal must be

stored

for subsequent use in between meals. Insulin and glucagon are the primary

hormones that coordinate and regulate the storage and release of the body's

fuel.

The Metabolic Effects of Insulin

Insulin is a polypeptide hormone that travels around the bloodstream. Most

of the cells in the body carry

receptors

for the molecule in their cell membranes. Once the hormone has become bound

to one of these receptors, the receptor gives a signal to the cell's

interior.

This signal leads to many enzyme controlled reactions which, in turn lead to

changes in the metabolism of the cell.

Many of the effects of insulin depend on the particular cell type in which

it stimulates. However, in nearly all of the cells that have insulin

receptors

in their cell membrane, the binding of insulin to the receptors leads to

increased glucose uptake of the cell.

The two types of cells that are the main exceptions are the brain and the

liver. However, this is only due to the fact that these cells are readily

permeable

to glucose, even in the absence of insulin. Liver cell membranes do contain

insulin and glucagon receptors, but binding of the hormone to them affects

cellular processes other than glucose permeability.

The animation below illustrates the way insulin brings about the increase in

glucose uptake.

Glucose enters the cells of the body through glucose transporter (GLUT)

proteins which are embedded within the cell membrane. This is a process

called facilitated

diffusion.

When insulin binds to it's receptor, the intracellular domain of the

receptor

changes shape slightly.

This sets off a chain of reactions. These reactions serve to activate

certain enzymes.

As a result, more glucose transporter proteins are released from

intracellular stores and move to the plasma membrane and become embedded

within it.

What do you think will be the effect of increased numbers of glucose

transporter proteins within the plasma membrane?

Less glucose will enter the blood via facilitated diffusion.

More glucose will enter the blood via facilitated diffusion.

The rate of glucose uptake by facilitated diffusion will increase.

The rate of glucose uptake via facilitated diffusion will decrease.

That's not all. You may be wondering what happens to the all this glucose

that is now entering the cells.

Another of the actions of insulin is to stimulate the rate at which glucose

is used up in cellular respiration. This occurs due to the fact that insulin

stimulates the activity of the some of the enzymes which carry out

glycolysis.

The most important body tissues in terms of insulin (and glucagon) action

are:

List of 3 items

1. The liver

2. The muscle

3. Adipose tissue (fat storage tissue)

list end

Below is a summary of the way insulin influences the physiological processes

within the cells of each of these tissues. The most important ones are

emphasised

by the pointing fingers.

A

indicates that the process stated is stimulated within the cells of that

tissue by the hormone.

Table with 8 columns and 11 rows

Liver

Muscle

Adipose

Stimulation of glucose uptake

Stimulation of cellular respiration

Stimulation of

glycogenesis

Inhibition of

glycogenolysis

Stimulation of amino acid uptake

Stimulation of protein synthesis

Inhibition of protein degradation

Stimulation of

fatty acid and triglyceride synthesis

Inhibition of lipolysis

Stimulation of lipoproteins uptake

table end

Take a look at the

metabolic map

which summarises nutrient flow after a meal.

The Metabolic Effects of Glucagon

Like insulin, glucagon is a polypeptide hormone. However, in contrast to

insulin, receptors for glucagon are not as abundant in cells throughout the

body.

The action of glucagon to increase blood glucose concentrations is largely

as a result of the effects it has on cells of the liver after binding to

membrane

receptors.

Table with 8 columns and 7 rows

The Liver

Muscle

Adipose

Stimulation of glycogenolysis

Inhibition of glycogenesis

Stimulation of

gluconeogenesis

Stimulation of lipolysis

Stimulation of

ketone formation

Stimulation of amino acid uptake

Factors Affecting the Secretion of Insulin and Glucagon

So now we know which cells secrete which of the two hormones. We will now

look at the stimuli for their secretion into the blood.

As you no doubt already know, one of the most important roles of insulin and

glucagon is to maintain constant levels of glucose in the blood and that

they

are secreted in response to fluctuations in blood glucose either side of

this

normal concentration.

The two hormones can do this because they act antagonistically to each

other. This means that they have opposite effects in terms of which way they

cause

blood glucose concentration to be driven after their secretion.

Insulin is secreted from the beta cells of the islets of Langerhans in

response to an increase in blood glucose levels. Therefore, what effect

would you

expect insulin to have on blood glucose concentration?

Insulin will have the following effect on blood glucose concentrations:

An increase.

No change.

A decrease.

Because glucagon acts antagonistically to insulin, this hormone serves to

increase blood glucose levels. Therefore, what do you think is the primary

stimulus

for it's secretion?

a decrease in blood glucose concentration below normal levels.

an increase in blood glucose concentration above normal levels.

However the situation is not as straight forward as it may seem. The

concentration of blood glucose is the most important physiological stimulus,

but there

are several other factors that influence secretion and indeed the inhibition

of insulin and glucagon. If you are studying beyond A Level it would be

helpful

to you if you were

familiar with these.

The Secretion of Insulin in Response to an Increased Blood Glucose

Concentration.

Take a look at the animation below. It will keep running for as long as you

stay on this page. It illustrates the way in which plasma concentrations of

glucose and insulin, in a normal adult, change following an oral glucose

load. This was in the form of 50g of glucose dissolved in water and was

given

following an overnight fast. The levels seen prior to administration of

glucose represent the basal plasma (blood) concentrations of the two

substances.

They are not on the same scale but that doesn't matter.

The main points to notice are:

List of 3 items

1. The concentration of glucose in the blood rises rapidly after the

ingestion of glucose (or a high carbohydrate meal).

Table with 3 columns and 2 rows

This shows that glucose is rapidly absorbed from the gut into the blood.

table end

2. The increase in blood glucose concentration is closely followed in time

by an increase in plasma insulin concentration.

Table with 3 columns and 2 rows

This shows that the beta cells are very sensitive to slight changes in blood

glucose and are capable of responding rapidly.

table end

3. Peak glucose concentration occurs within the first hour and a return to

basal levels within two hours.

This highlights the speed with which insulin brings about the metabolic

changes that serve to remove glucose from the blood.

list end

How do the beta cells know when to stop secreting insulin?

As insulin carries out it's function and starts to bring blood glucose

concentrations back down to normal, then this removes the stimulus that

tells the

beta cells to secrete the insulin in the first place . As a result the beta

cells become less and less stimulated and so the rate of secretion of

insulin

declines in parallel to the rate of decline in blood glucose concentration.

This is an example of

negative feedback.

Ok, so we've had a look at how insulin is secreted in response to elevated

blood glucose levels. However, one thing that is easily forgotten is the

fact

that something else is happening at the same time. That is that while

insulin secretion is being stimulated, glucagon secretion is being

inhibited.

After a high carbohydrate meal, the ratio of insulin:glucagon concentrations

can reach 10:1.

Take a look at the next graph, it is the same as the first but with glucagon

concentration added. The key things to notice are:

List of 3 items

1. The initial increase in glucagon concentration parallels the increase in

glucose.

Table with 3 columns and 2 rows

This is due to stimulation of the alpha cells by nerve impulses triggered by

the presence of " food " in the gut.

table end

2. The glucagon concentration begins to fall shortly after glucose

concentration begins to rise.

Table with 4 columns and 2 rows

The alpha cells detect that glucose concentrations are rising above normal

levels. This change starts processes within the cells that inhibit the

secretion

of glucagon.

table end

3. After blood glucose and insulin levels return to normal, the

concentration of glucagon begins to increase again back towards basal

levels.

list end

Here's another easy question:

Can you figure out why the glucagon levels start to rise again at the point

in which they do?

If you want to look at a still image of the graph,

click here.

Because the glucagon concentration has fallen to its lowest possible level

and can't decrease any further.

Because the glucose concentration has reached its peak.

Because the inhibition of glucagon secretion has been removed.

The secretion of glucagon in response to a decrease in blood glucose

concentration.

In direct contrast to insulin, a decrease in blood glucose concentration

stimulates glucagon secretion.Therefore, circulating levels of glucagon tend

to

be highest during periods of starvation (fasting)or prolonged exercise (e.g.

running a marathon). During these times, blood glucose concentrations are

at their lowest. The ratio of insulin:glucagon concentrations is

approximately 1:2.

Man Exercising

The glucagon brings about changes in the body's metabolism that raise blood

glucose concentration back to normal. The alpha cells detect that glucose

concentrations

are returning to normal and stop secreting glucagon. Again, this is an

example of negative feedback control.

Summary

So, as you can see, the pattern of insulin and glucagon secretion is an

example of one of the body's control processes whereby the " steady state "

blood

glucose concentration is maintained. This is achieved by means of a delicate

balance between two hormones that have opposite effects. The whole thing is

controlled by a negative feedback system.

Take a look at the

diagram

summarising the whole process.

But what exactly are these effects? What effects do the hormones have on the

body's metabolism that cause the blood glucose levels to be returned to

normal?

These are the questions addressed in the next section.

An Overview of Diabetes

Diabetes Mellitus

OVERVIEW

FACTS AND FIGURES

WHAT CAUSES DIABETES?

COMPLICATIONS OF DIABETES

MANAGING DIABETES

LINKS

Overview

Diabetes mellitus is a disease that arises as a result of insufficient

insulin being produced by the beta cells, or the insulin that is produced

does not

function properly.

There are two main types of diabetes:

List of 1 items

1. Insulin-dependent diabetes (also known as Type 1 diabetes or juvenile

diabetes)

list end

List of 1 items

2. Non-insulin-dependent diabetes (also known as Type 2 diabetes or maturity

onset diabetes)

list end

The common characteristic of both types of diabetes is an abnormally high

blood glucose concentration.

The table below summarises some of the main characteristics of each form of

the disease.

Table with 2 columns and 16 rows

Insulin Dependent Non Insulin Dependent

Diabetes Diabetes

(Type 1) (Type

2)

Severe lack of insulin due to the The beta cells do not

produce

destruction of beta cells. sufficient

insulin or the insulin that

is produced becomes less effective.

Develops rapidly over time. Develops more

gradually over time.

Usually appears before the age of 35 Usually appears in people

over the

and most often between 10 and 16 age of 40 (hence maturity

onset

years of age (hence juvenile diabetes). diabetes).

Accounts for about 10% of all Accounts for about 90%

of all

diabetics.

diabetics.

table end

A Few Facts and Figures

List of 1 items

.. In the U.K. an estimated 1.4 million people are known to have diabetes

with possibly up to a million more undiagnosed.

list end

List of 1 items

.. Diabetes is the fourth leading cause of death in the most developed

countries.

list end

List of 1 items

.. It is projected that between 1995 and 2025, the number of the worldwide

adult population affected by diabetes mellitus will increase by 122%

This is mainly due to population ageing and growth, increasing incidence of

obesity, increases in diets high in saturated fats and people tending to

lead

lifestyles that lack regular exercise.

list end

What causes diabetes?

Type 1 diabetes

In type 1 diabetes, the beta cells are destroyed by an autoimmune process

whereby the body's immune system recognises the cells as " foreign " rather

than

" self " and therefore attacks them.

The cause of the autoimmune disorder is currently subject to much research.

At least two major components are though to contribute to the disease

appearring.

The first is a genetic component by which certain individuals, with defects

in certain genes, have an increased susceptibility. So far, two genes have

been identified that appear to put an individual at risk, but there are

certain to be others involved. The genetic component is not, in itself,

sufficient

to cause the autoimmunity. The effects of an as yet unidentified

environmental component are required to produce the disease in these

suceptible individuals.

Viruses have been suggested as likely candidates.

Type 2 diabetes

The cause of type 2 diabetes is thought to be due to both defects in the

beta cells (so that less insulin is produced) and also to the decrease in

insulin's

ability to stimulate the uptake of glucose in tissues (a condition referred

to as

insulin resistance).

The cause of this insulin resistence is not fully known although it has been

linked to defects in the action of insulin after it has bound to the

receptor

on the surface of cells (i.e. the cascade of reactions that were mentioned

earlier).

In many cases, patients with this form of the disease are obese but the

exact link between the two remains unclear.

As in type 1 diabetes, there is a genetic influence. In fact, type 2

diabetes tends to run in families even more strongly than type 1. There is

nearly a

100% chance that if one genetically identical twin develops type 2 diabetes,

the other will also, even if they are raised in completely different

environments.

Diabetes Mellitus Can Result in both Short and Long-Term Complications

Diabetes mellitus is a disease that has traditionally been studied at great

length by scientists in an attempt to make it easier for those sufferring

from

the disease to keep their blood glucose levels under control. Such intensive

research has meant that diabetics are able to lead relatively normal

lifestyles

provided they adopt a responsible approach in the management of the

condition. If the correct approach is achieved and maintained, then the risk

of developing

diabetic complications is minimised greatly. The section below outlines the

mechanisms by which these complications arise if blood glucose levels are

not

controlled.

Short-Term, Acute Complications

In the absence of either insulin secretion or insulin action, the blood

glucose concentation

rises quickly

and steeply (hyperglycaemia) after glucose or carbohydrate intake. As a

result, the amount of glucose that gets filtered into the kidney tubules

increases

also. The capacity for the kidney to reabsorb glucose from the urine is

limited. If the amount of glucose that enters the tubules is too high, (i.e.

if

it exceeds the glucose threshold), glucose appears in the urine. This

condition is termed glucosuria. Because of osmotic effects, glucose in the

urine

draws with it considerable amounts of water, which will be excreted along

with the glucose. As a result, urine volume and frequency increases

(polyuria)

and the diabetic individual is frequently dehydrated and is nearly always

thirsty

(polydipsia).

In type 1 diabetics, the unopposed actions of glucagon result in increased

ketone formation by the liver. These ketones are acidic and their build up

considerably

lowers blood pH and disturbs the acid/base balance of the body. This

condition is termed ketoacidosis and is the largest cause of death amongst

diabetics

under the age of 30. As with glucose, if ketones reach high enough

concentrations in the blood, they will begin to appear in the urine. Ketones

carry cations,

such as sodium (Na+) and potassium (K+), with them into the urine leading to

electrolye imbalances in the body.

Consequences of these complications may include abdominal pain, vomiting,

sweet-smelling breath and severe dehydration. Severe cases can lead to

diabetic

coma and death.

Long-Term, Chronic Complications

Several secondary complications usually accompany long-standing diabetes

mellitus. These often involve gradual changes that develop over a period of

years

and may shorten the life expectancy of diabetic individuals. The most common

involve the vascular system. Changes much like those seen in atherosclerosis

lead to narrowing of the arteries supplying the brain, heart and lower

limbs. This increases susceptibility to strokes, heart attack and amputation

of

the limbs.

Impairment to the vascular system is thought to be the reason behind

conditions such as:

Table with 3 columns and 8 rows

Retinopathy

Lesions in the small blood vessels and capillaries supplying the retina of

the eye.

Every year thousands of diabetics become blind as a result.

Neuropathy

Impairment of the function of the autonomic nerves.

Leads to abnormalities in the function of the gastrointestinal tract and

bladder and also loss of feeling in lower extremities.

Nephropathy

Lesions in the small blood vessels and capillaries supplying the kidney.

Can lead to kidney disease.

table end

If hypoglycaemia is prolonged, this can lead to the condition known as

glucose toxicity whereby cellular proteins, such as ion channels, receptors

etc.,

become glycosylated (polysaccharide side chains added to them) and their

function impaired.

As mentioned, the likelihood of such conditions as these developing, is

greatly dependent on the long-term control of blood glucose levels by the

patient.

Good control throughout life is highly effective in minimising this risk.

The section below outlines the ways in which the control of blood glucose in

diabetics can be achieved.

Managing Diabetes

If you had lived before the turn of the 20th century and developed diabetes

mellitus, you would have faced the prospect of increasing lethargy, gradual

loss of weight and certain premature death. Historically, " treatments "

included excessive feeding of sugar, a diet consisting almost exclusively of

potatoes

and also, for some reason, bleeding!!

For diabetic individuals, the adherence to a " sensible " diet is crucial. It

needs to be low in sugar in order to help prevent blood glucose levels

becoming,

and staying too high. It also needs to be low in fat but high in complex

carbohydrates such as bread, pasta, potatoes etc. These take a long time to

digest

and so elicit a relatively slow increase in blood glucose.

For type 1 diabetics, the constant monitoring of their blood glucose levels

is required. Methods include the use of biochemical test strips which are

impregnated

with a reagent that changes colour after a drop of blood is placed onto it.

The shade of the colour is compared to a standard colour chart to determine

the amount of glucose present in the blood. More technical equipment such as

electronic hand held meters contain electrodes. Once a drop of blood is

placed

onto the electrode, it generates a readout of the glucose concentration.

Type 1 diabetics are requred to inject themselves with insulin at mealtimes

and other intervals throughout the day to keep blood glucose levels under

the

best possible control. Convenient " pocket pens " allow injection of a set

amount of insulin without the need to fill syringes from a separate insulin

container

prior to injection. Portable insulin pumps were one of the first new

technologies to be introduced into diabetes care. A small pump containing

the reservoir

of insulin is worn around the waist. A fine catheter delivers a controlled

infusion of insulin into the tissue under the skin with patient-activated

boosts

at mealtimes.

A major problem that presents itself to type 1 diabetics lies in the risk of

injecting too much insulin, taking too much exercise or too little food, or

a combination of these factors. In these cases, blood glucose levels drop

too low and, if unchecked, will lead to hypoglycaemia. The threshold for

hypoglycaemia

is approximately 3mM glucose, at which point the majority of diabetics sense

the onset of a " hypo. " During a hypo, the individual initially develops a

headache and nausea. The full consequences are distressing; behaviour

becomes increasingly erratic and bizzare leading to convulsions,

unconciousness followed

by coma and death due to lack of glucose to the brain (the brain can't use

any other fuel source).

Which of these two remedies would you suggest for severe hypoglycaemia?

Injection of insulin and glucose tablets.

The injection of both insulin and glucagon.

Glucose tablets and the injection of glucagon.

The injection of glucagon and vigourous exercise.

The managment of type 2 diabetes can often be achieved through the adherence

to a strict diet alone. If this isn't the case, it is achieved through the

combination of diet and hypoglycaemic drugs such as:

List of 1 items

.. Sulfonylureas: stimulate insulin secretion from the beta cells of the

islets.

list end

List of 1 items

.. Biguanides: have actions similar to those of insulin.

list end

List of 1 items

.. Alpha-glucosidase inhibitors: inhibit alpha-glucosidase, an enzyme

responsible for starch and sucrose digestion in the gut.

list end

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

yes, this is a very complicated article! but thanks, anyway.

Re: Questions looking for answers

Thanks for your response, which prompted me to do more research on

the internet. I found the following, which is a good primmer on metabolism

and diabetes in normal people. I like your simple explanation much better

than the one presented below:

The Pancreas

The topic of insulin and glucagon begins here, in the pancreas.The pancreas

is located in the abdominal cavity adjacent to the upper part of the small

intestine

as shown in the diagram opposite.

The pancreas serves TWO FUNCTIONS which are carried out by two different

groups of cells within the organ. These two groups of cells are designated

as the

exocrine

and the endocrine portions of the pancreas. If a cell is exocrine it does

not secrete it's products into the bloodstream. If a cell is endocrine, it

does.

In the context of insulin and glucagon, we only need to concern ourselves

with the endocrine pancreas. This is what we will now go on to look at.

Anatomical location of the pancreas

The Endocrine Pancreas

The endocrine pancreas consists of groups of cells known as the islets of

Langerhans which are embedded in the exocrine portion of the gland as

illustrated

in the diagram below.

A schematic illustration of a cross section of the pancreas showing the

relationship of the islets (endocrine cells) to the exocrine cells.

The islets of Langerhans only make up about 1-2% of the total pancreas cells

although the average human pancreas has about one million of them.

It is from these islets that the hormones insulin and glucagon are secreted.

A Delta cell is a cell that secretes somatostatin.

As you can see from the diagram opposite, each islet is richly supplied with

blood vessels. Insulin and glucagon are secreted out of the islet cells

directly

into these blood vessels from where they can travel to all parts of the

body. This is why the islets are called endocrine cells.

Islets are composed of four major cell types. Each one synthesises and

secretes a different hormone although we only need to concern ourselves with

two

of them. These are the alpha and the beta cells.

Cells of the Islets of Langerhans

Remember............

ALPHA cells synthesise and secrete GLUCAGON

BETA cells synthesise and secrete INSULIN

Metabolism

The Metabolic Effects of Insulin and Glucagon

Even while at rest or sleeping, the body is continually using energy to

drive the vital processes that keep us alive. Physical activity increases

energy

requirements above those in the basal (resting) state.

However, although energy use is continuous, the intake of energy in the form

of food is intermittent. Thus, excess fuels taken in with a meal must be

stored

for subsequent use in between meals. Insulin and glucagon are the primary

hormones that coordinate and regulate the storage and release of the body's

fuel.

The Metabolic Effects of Insulin

Insulin is a polypeptide hormone that travels around the bloodstream. Most

of the cells in the body carry

receptors

for the molecule in their cell membranes. Once the hormone has become bound

to one of these receptors, the receptor gives a signal to the cell's

interior.

This signal leads to many enzyme controlled reactions which, in turn lead to

changes in the metabolism of the cell.

Many of the effects of insulin depend on the particular cell type in which

it stimulates. However, in nearly all of the cells that have insulin

receptors

in their cell membrane, the binding of insulin to the receptors leads to

increased glucose uptake of the cell.

The two types of cells that are the main exceptions are the brain and the

liver. However, this is only due to the fact that these cells are readily

permeable

to glucose, even in the absence of insulin. Liver cell membranes do contain

insulin and glucagon receptors, but binding of the hormone to them affects

cellular processes other than glucose permeability.

The animation below illustrates the way insulin brings about the increase in

glucose uptake.

Glucose enters the cells of the body through glucose transporter (GLUT)

proteins which are embedded within the cell membrane. This is a process

called facilitated

diffusion.

When insulin binds to it's receptor, the intracellular domain of the

receptor

changes shape slightly.

This sets off a chain of reactions. These reactions serve to activate

certain enzymes.

As a result, more glucose transporter proteins are released from

intracellular stores and move to the plasma membrane and become embedded

within it.

What do you think will be the effect of increased numbers of glucose

transporter proteins within the plasma membrane?

Less glucose will enter the blood via facilitated diffusion.

More glucose will enter the blood via facilitated diffusion.

The rate of glucose uptake by facilitated diffusion will increase.

The rate of glucose uptake via facilitated diffusion will decrease.

That's not all. You may be wondering what happens to the all this glucose

that is now entering the cells.

Another of the actions of insulin is to stimulate the rate at which glucose

is used up in cellular respiration. This occurs due to the fact that insulin

stimulates the activity of the some of the enzymes which carry out

glycolysis.

The most important body tissues in terms of insulin (and glucagon) action

are:

List of 3 items

1. The liver

2. The muscle

3. Adipose tissue (fat storage tissue)

list end

Below is a summary of the way insulin influences the physiological processes

within the cells of each of these tissues. The most important ones are

emphasised

by the pointing fingers.

A

indicates that the process stated is stimulated within the cells of that

tissue by the hormone.

Table with 8 columns and 11 rows

Liver

Muscle

Adipose

Stimulation of glucose uptake

Stimulation of cellular respiration

Stimulation of

glycogenesis

Inhibition of

glycogenolysis

Stimulation of amino acid uptake

Stimulation of protein synthesis

Inhibition of protein degradation

Stimulation of

fatty acid and triglyceride synthesis

Inhibition of lipolysis

Stimulation of lipoproteins uptake

table end

Take a look at the

metabolic map

which summarises nutrient flow after a meal.

The Metabolic Effects of Glucagon

Like insulin, glucagon is a polypeptide hormone. However, in contrast to

insulin, receptors for glucagon are not as abundant in cells throughout the

body.

The action of glucagon to increase blood glucose concentrations is largely

as a result of the effects it has on cells of the liver after binding to

membrane

receptors.

Table with 8 columns and 7 rows

The Liver

Muscle

Adipose

Stimulation of glycogenolysis

Inhibition of glycogenesis

Stimulation of

gluconeogenesis

Stimulation of lipolysis

Stimulation of

ketone formation

Stimulation of amino acid uptake

Factors Affecting the Secretion of Insulin and Glucagon

So now we know which cells secrete which of the two hormones. We will now

look at the stimuli for their secretion into the blood.

As you no doubt already know, one of the most important roles of insulin and

glucagon is to maintain constant levels of glucose in the blood and that

they

are secreted in response to fluctuations in blood glucose either side of

this

normal concentration.

The two hormones can do this because they act antagonistically to each

other. This means that they have opposite effects in terms of which way they

cause

blood glucose concentration to be driven after their secretion.

Insulin is secreted from the beta cells of the islets of Langerhans in

response to an increase in blood glucose levels. Therefore, what effect

would you

expect insulin to have on blood glucose concentration?

Insulin will have the following effect on blood glucose concentrations:

An increase.

No change.

A decrease.

Because glucagon acts antagonistically to insulin, this hormone serves to

increase blood glucose levels. Therefore, what do you think is the primary

stimulus

for it's secretion?

a decrease in blood glucose concentration below normal levels.

an increase in blood glucose concentration above normal levels.

However the situation is not as straight forward as it may seem. The

concentration of blood glucose is the most important physiological stimulus,

but there

are several other factors that influence secretion and indeed the inhibition

of insulin and glucagon. If you are studying beyond A Level it would be

helpful

to you if you were

familiar with these.

The Secretion of Insulin in Response to an Increased Blood Glucose

Concentration.

Take a look at the animation below. It will keep running for as long as you

stay on this page. It illustrates the way in which plasma concentrations of

glucose and insulin, in a normal adult, change following an oral glucose

load. This was in the form of 50g of glucose dissolved in water and was

given

following an overnight fast. The levels seen prior to administration of

glucose represent the basal plasma (blood) concentrations of the two

substances.

They are not on the same scale but that doesn't matter.

The main points to notice are:

List of 3 items

1. The concentration of glucose in the blood rises rapidly after the

ingestion of glucose (or a high carbohydrate meal).

Table with 3 columns and 2 rows

This shows that glucose is rapidly absorbed from the gut into the blood.

table end

2. The increase in blood glucose concentration is closely followed in time

by an increase in plasma insulin concentration.

Table with 3 columns and 2 rows

This shows that the beta cells are very sensitive to slight changes in blood

glucose and are capable of responding rapidly.

table end

3. Peak glucose concentration occurs within the first hour and a return to

basal levels within two hours.

This highlights the speed with which insulin brings about the metabolic

changes that serve to remove glucose from the blood.

list end

How do the beta cells know when to stop secreting insulin?

As insulin carries out it's function and starts to bring blood glucose

concentrations back down to normal, then this removes the stimulus that

tells the

beta cells to secrete the insulin in the first place . As a result the beta

cells become less and less stimulated and so the rate of secretion of

insulin

declines in parallel to the rate of decline in blood glucose concentration.

This is an example of

negative feedback.

Ok, so we've had a look at how insulin is secreted in response to elevated

blood glucose levels. However, one thing that is easily forgotten is the

fact

that something else is happening at the same time. That is that while

insulin secretion is being stimulated, glucagon secretion is being

inhibited.

After a high carbohydrate meal, the ratio of insulin:glucagon concentrations

can reach 10:1.

Take a look at the next graph, it is the same as the first but with glucagon

concentration added. The key things to notice are:

List of 3 items

1. The initial increase in glucagon concentration parallels the increase in

glucose.

Table with 3 columns and 2 rows

This is due to stimulation of the alpha cells by nerve impulses triggered by

the presence of " food " in the gut.

table end

2. The glucagon concentration begins to fall shortly after glucose

concentration begins to rise.

Table with 4 columns and 2 rows

The alpha cells detect that glucose concentrations are rising above normal

levels. This change starts processes within the cells that inhibit the

secretion

of glucagon.

table end

3. After blood glucose and insulin levels return to normal, the

concentration of glucagon begins to increase again back towards basal

levels.

list end

Here's another easy question:

Can you figure out why the glucagon levels start to rise again at the point

in which they do?

If you want to look at a still image of the graph,

click here.

Because the glucagon concentration has fallen to its lowest possible level

and can't decrease any further.

Because the glucose concentration has reached its peak.

Because the inhibition of glucagon secretion has been removed.

The secretion of glucagon in response to a decrease in blood glucose

concentration.

In direct contrast to insulin, a decrease in blood glucose concentration

stimulates glucagon secretion.Therefore, circulating levels of glucagon tend

to

be highest during periods of starvation (fasting)or prolonged exercise (e.g.

running a marathon). During these times, blood glucose concentrations are

at their lowest. The ratio of insulin:glucagon concentrations is

approximately 1:2.

Man Exercising

The glucagon brings about changes in the body's metabolism that raise blood

glucose concentration back to normal. The alpha cells detect that glucose

concentrations

are returning to normal and stop secreting glucagon. Again, this is an

example of negative feedback control.

Summary

So, as you can see, the pattern of insulin and glucagon secretion is an

example of one of the body's control processes whereby the " steady state "

blood

glucose concentration is maintained. This is achieved by means of a delicate

balance between two hormones that have opposite effects. The whole thing is

controlled by a negative feedback system.

Take a look at the

diagram

summarising the whole process.

But what exactly are these effects? What effects do the hormones have on the

body's metabolism that cause the blood glucose levels to be returned to

normal?

These are the questions addressed in the next section.

An Overview of Diabetes

Diabetes Mellitus

OVERVIEW

FACTS AND FIGURES

WHAT CAUSES DIABETES?

COMPLICATIONS OF DIABETES

MANAGING DIABETES

LINKS

Overview

Diabetes mellitus is a disease that arises as a result of insufficient

insulin being produced by the beta cells, or the insulin that is produced

does not

function properly.

There are two main types of diabetes:

List of 1 items

1. Insulin-dependent diabetes (also known as Type 1 diabetes or juvenile

diabetes)

list end

List of 1 items

2. Non-insulin-dependent diabetes (also known as Type 2 diabetes or maturity

onset diabetes)

list end

The common characteristic of both types of diabetes is an abnormally high

blood glucose concentration.

The table below summarises some of the main characteristics of each form of

the disease.

Table with 2 columns and 16 rows

Insulin Dependent Non Insulin Dependent

Diabetes Diabetes

(Type 1) (Type

2)

Severe lack of insulin due to the The beta cells do not

produce

destruction of beta cells. sufficient

insulin or the insulin that

is produced becomes less effective.

Develops rapidly over time. Develops more

gradually over time.

Usually appears before the age of 35 Usually appears in people

over the

and most often between 10 and 16 age of 40 (hence maturity

onset

years of age (hence juvenile diabetes). diabetes).

Accounts for about 10% of all Accounts for about 90%

of all

diabetics.

diabetics.

table end

A Few Facts and Figures

List of 1 items

.. In the U.K. an estimated 1.4 million people are known to have diabetes

with possibly up to a million more undiagnosed.

list end

List of 1 items

.. Diabetes is the fourth leading cause of death in the most developed

countries.

list end

List of 1 items

.. It is projected that between 1995 and 2025, the number of the worldwide

adult population affected by diabetes mellitus will increase by 122%

This is mainly due to population ageing and growth, increasing incidence of

obesity, increases in diets high in saturated fats and people tending to

lead

lifestyles that lack regular exercise.

list end

What causes diabetes?

Type 1 diabetes

In type 1 diabetes, the beta cells are destroyed by an autoimmune process

whereby the body's immune system recognises the cells as " foreign " rather

than

" self " and therefore attacks them.

The cause of the autoimmune disorder is currently subject to much research.

At least two major components are though to contribute to the disease

appearring.

The first is a genetic component by which certain individuals, with defects

in certain genes, have an increased susceptibility. So far, two genes have

been identified that appear to put an individual at risk, but there are

certain to be others involved. The genetic component is not, in itself,

sufficient

to cause the autoimmunity. The effects of an as yet unidentified

environmental component are required to produce the disease in these

suceptible individuals.

Viruses have been suggested as likely candidates.

Type 2 diabetes

The cause of type 2 diabetes is thought to be due to both defects in the

beta cells (so that less insulin is produced) and also to the decrease in

insulin's

ability to stimulate the uptake of glucose in tissues (a condition referred

to as

insulin resistance).

The cause of this insulin resistence is not fully known although it has been

linked to defects in the action of insulin after it has bound to the

receptor

on the surface of cells (i.e. the cascade of reactions that were mentioned

earlier).

In many cases, patients with this form of the disease are obese but the

exact link between the two remains unclear.

As in type 1 diabetes, there is a genetic influence. In fact, type 2

diabetes tends to run in families even more strongly than type 1. There is

nearly a

100% chance that if one genetically identical twin develops type 2 diabetes,

the other will also, even if they are raised in completely different

environments.

Diabetes Mellitus Can Result in both Short and Long-Term Complications

Diabetes mellitus is a disease that has traditionally been studied at great

length by scientists in an attempt to make it easier for those sufferring

from

the disease to keep their blood glucose levels under control. Such intensive

research has meant that diabetics are able to lead relatively normal

lifestyles

provided they adopt a responsible approach in the management of the

condition. If the correct approach is achieved and maintained, then the risk

of developing

diabetic complications is minimised greatly. The section below outlines the

mechanisms by which these complications arise if blood glucose levels are

not

controlled.

Short-Term, Acute Complications

In the absence of either insulin secretion or insulin action, the blood

glucose concentation

rises quickly

and steeply (hyperglycaemia) after glucose or carbohydrate intake. As a

result, the amount of glucose that gets filtered into the kidney tubules

increases

also. The capacity for the kidney to reabsorb glucose from the urine is

limited. If the amount of glucose that enters the tubules is too high, (i.e.

if

it exceeds the glucose threshold), glucose appears in the urine. This

condition is termed glucosuria. Because of osmotic effects, glucose in the

urine

draws with it considerable amounts of water, which will be excreted along

with the glucose. As a result, urine volume and frequency increases

(polyuria)

and the diabetic individual is frequently dehydrated and is nearly always

thirsty

(polydipsia).

In type 1 diabetics, the unopposed actions of glucagon result in increased

ketone formation by the liver. These ketones are acidic and their build up

considerably

lowers blood pH and disturbs the acid/base balance of the body. This

condition is termed ketoacidosis and is the largest cause of death amongst

diabetics

under the age of 30. As with glucose, if ketones reach high enough

concentrations in the blood, they will begin to appear in the urine. Ketones

carry cations,

such as sodium (Na+) and potassium (K+), with them into the urine leading to

electrolye imbalances in the body.

Consequences of these complications may include abdominal pain, vomiting,

sweet-smelling breath and severe dehydration. Severe cases can lead to

diabetic

coma and death.

Long-Term, Chronic Complications

Several secondary complications usually accompany long-standing diabetes

mellitus. These often involve gradual changes that develop over a period of

years

and may shorten the life expectancy of diabetic individuals. The most common

involve the vascular system. Changes much like those seen in atherosclerosis

lead to narrowing of the arteries supplying the brain, heart and lower

limbs. This increases susceptibility to strokes, heart attack and amputation

of

the limbs.

Impairment to the vascular system is thought to be the reason behind

conditions such as:

Table with 3 columns and 8 rows

Retinopathy

Lesions in the small blood vessels and capillaries supplying the retina of

the eye.

Every year thousands of diabetics become blind as a result.

Neuropathy

Impairment of the function of the autonomic nerves.

Leads to abnormalities in the function of the gastrointestinal tract and

bladder and also loss of feeling in lower extremities.

Nephropathy

Lesions in the small blood vessels and capillaries supplying the kidney.

Can lead to kidney disease.

table end

If hypoglycaemia is prolonged, this can lead to the condition known as

glucose toxicity whereby cellular proteins, such as ion channels, receptors

etc.,

become glycosylated (polysaccharide side chains added to them) and their

function impaired.

As mentioned, the likelihood of such conditions as these developing, is

greatly dependent on the long-term control of blood glucose levels by the

patient.

Good control throughout life is highly effective in minimising this risk.

The section below outlines the ways in which the control of blood glucose in

diabetics can be achieved.

Managing Diabetes

If you had lived before the turn of the 20th century and developed diabetes

mellitus, you would have faced the prospect of increasing lethargy, gradual

loss of weight and certain premature death. Historically, " treatments "

included excessive feeding of sugar, a diet consisting almost exclusively of

potatoes

and also, for some reason, bleeding!!

For diabetic individuals, the adherence to a " sensible " diet is crucial. It

needs to be low in sugar in order to help prevent blood glucose levels

becoming,

and staying too high. It also needs to be low in fat but high in complex

carbohydrates such as bread, pasta, potatoes etc. These take a long time to

digest

and so elicit a relatively slow increase in blood glucose.

For type 1 diabetics, the constant monitoring of their blood glucose levels

is required. Methods include the use of biochemical test strips which are

impregnated

with a reagent that changes colour after a drop of blood is placed onto it.

The shade of the colour is compared to a standard colour chart to determine

the amount of glucose present in the blood. More technical equipment such as

electronic hand held meters contain electrodes. Once a drop of blood is

placed

onto the electrode, it generates a readout of the glucose concentration.

Type 1 diabetics are requred to inject themselves with insulin at mealtimes

and other intervals throughout the day to keep blood glucose levels under

the

best possible control. Convenient " pocket pens " allow injection of a set

amount of insulin without the need to fill syringes from a separate insulin

container

prior to injection. Portable insulin pumps were one of the first new

technologies to be introduced into diabetes care. A small pump containing

the reservoir

of insulin is worn around the waist. A fine catheter delivers a controlled

infusion of insulin into the tissue under the skin with patient-activated

boosts

at mealtimes.

A major problem that presents itself to type 1 diabetics lies in the risk of

injecting too much insulin, taking too much exercise or too little food, or

a combination of these factors. In these cases, blood glucose levels drop

too low and, if unchecked, will lead to hypoglycaemia. The threshold for

hypoglycaemia

is approximately 3mM glucose, at which point the majority of diabetics sense

the onset of a " hypo. " During a hypo, the individual initially develops a

headache and nausea. The full consequences are distressing; behaviour

becomes increasingly erratic and bizzare leading to convulsions,

unconciousness followed

by coma and death due to lack of glucose to the brain (the brain can't use

any other fuel source).

Which of these two remedies would you suggest for severe hypoglycaemia?

Injection of insulin and glucose tablets.

The injection of both insulin and glucagon.

Glucose tablets and the injection of glucagon.

The injection of glucagon and vigourous exercise.

The managment of type 2 diabetes can often be achieved through the adherence

to a strict diet alone. If this isn't the case, it is achieved through the

combination of diet and hypoglycaemic drugs such as:

List of 1 items

.. Sulfonylureas: stimulate insulin secretion from the beta cells of the

islets.

list end

List of 1 items

.. Biguanides: have actions similar to those of insulin.

list end

List of 1 items

.. Alpha-glucosidase inhibitors: inhibit alpha-glucosidase, an enzyme

responsible for starch and sucrose digestion in the gut.

list end

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose level

> reading and exercise:

> Prior to exercising for an hour and fifteen minutes, which includes

> walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of 160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

Well, like Harry sid; you start the exercise with it a little higher than it

normally is. You wil then burn up the extra glucose without makking your

liver put out more glucogon for more energy. However, some people wil have

a highter blood sugar after exerciseing, but may have a sudden drop an hour

or so later.

Re: Questions looking for answers

Pat I cannot recall, how do you exercise without geting your sugar to go

high?

Regards,

Questions looking for answers

What causes this?

First, I will note the following observation regarding my glucose level

reading and exercise:

Prior to exercising for an hour and fifteen minutes, which includes

walking

approximately 1.9 miles and several sets of isometric exercises,

a glucose of 120 or less yields a post exercise glucose reading of 160

plus

or minus 10 points, and I feel exhausted for a long time.

If I have a pre-exercise glucose level reading of 150 to 160, my post

exercise glucose level reading is usually around 75 plus or minus 10

points,

and I feel fairly good.

Do others experience this?

What are the explanations for these observations? Post this message to

other forums if you wish. I would really like to know.

[Guest guest]

Well, like Harry sid; you start the exercise with it a little higher than it

normally is. You wil then burn up the extra glucose without makking your

liver put out more glucogon for more energy. However, some people wil have

a highter blood sugar after exerciseing, but may have a sudden drop an hour

or so later.

Re: Questions looking for answers

Pat I cannot recall, how do you exercise without geting your sugar to go

high?

Regards,

Questions looking for answers

What causes this?

First, I will note the following observation regarding my glucose level

reading and exercise:

Prior to exercising for an hour and fifteen minutes, which includes

walking

approximately 1.9 miles and several sets of isometric exercises,

a glucose of 120 or less yields a post exercise glucose reading of 160

plus

or minus 10 points, and I feel exhausted for a long time.

If I have a pre-exercise glucose level reading of 150 to 160, my post

exercise glucose level reading is usually around 75 plus or minus 10

points,

and I feel fairly good.

Do others experience this?

What are the explanations for these observations? Post this message to

other forums if you wish. I would really like to know.

[Guest guest]

,

Now, somehow, I can understand this email. It is written in a form which

I can comprehend.

The technical article was very, very good but, unfortunately, it was

right at the top of my comprehension modules.

This is actually good as it causes me to have to crawl out of my comfort

zone and use that matter which holds my hair down on my scalp. This

causes me considerable pain and probably will also contribute to the

raising of all sort of sugars in my body and I am not even a Diabetic.

Take care and keep it up!

Cy, the Ancient One & Grady...

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

,

Now, somehow, I can understand this email. It is written in a form which

I can comprehend.

The technical article was very, very good but, unfortunately, it was

right at the top of my comprehension modules.

This is actually good as it causes me to have to crawl out of my comfort

zone and use that matter which holds my hair down on my scalp. This

causes me considerable pain and probably will also contribute to the

raising of all sort of sugars in my body and I am not even a Diabetic.

Take care and keep it up!

Cy, the Ancient One & Grady...

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

You still have hair? (sorry, you set yourself up for that one!)

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

You still have hair? (sorry, you set yourself up for that one!)

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

You still have hair? (sorry, you set yourself up for that one!)

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points,

> and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

Yes, I still have hair although it is not nearly as plentiful as it was

and much of what is left is now a different color than the jet black it

used to be.

I have another question. Ken from Canada has a reading of 6.4 or so on

his glucose meter. What does this mean? Do they have different

measurements in Canada? If so, how do you correlate the readings with

what we use in the States?

Cy, the really confused Ancient One...

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points, and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

Yes, I still have hair although it is not nearly as plentiful as it was

and much of what is left is now a different color than the jet black it

used to be.

I have another question. Ken from Canada has a reading of 6.4 or so on

his glucose meter. What does this mean? Do they have different

measurements in Canada? If so, how do you correlate the readings with

what we use in the States?

Cy, the really confused Ancient One...

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points, and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

Yes, I still have hair although it is not nearly as plentiful as it was

and much of what is left is now a different color than the jet black it

used to be.

I have another question. Ken from Canada has a reading of 6.4 or so on

his glucose meter. What does this mean? Do they have different

measurements in Canada? If so, how do you correlate the readings with

what we use in the States?

Cy, the really confused Ancient One...

Re: Questions looking for answers

Ok I am confused I thought if you had a high reading that doing some

excise would bring it down does this mean i don't have to excise

Questions looking for answers

>

>

> What causes this?

> First, I will note the following observation regarding my glucose

> level reading and exercise: Prior to exercising for an hour and

> fifteen minutes, which includes walking

> approximately 1.9 miles and several sets of isometric exercises,

> a glucose of 120 or less yields a post exercise glucose reading of

160

> plus

> or minus 10 points, and I feel exhausted for a long time.

> If I have a pre-exercise glucose level reading of 150 to 160, my post

> exercise glucose level reading is usually around 75 plus or minus 10

> points, and I feel fairly good.

> Do others experience this?

> What are the explanations for these observations? Post this message

to

> other forums if you wish. I would really like to know.

>

>

>

>

>

>

>

[Guest guest]

yes, good explanation Pat! Thanks!

Regards,

Questions looking for answers

> >

> >

> > What causes this?

> > First, I will note the following observation regarding my glucose

> > level reading and exercise: Prior to exercising for an hour and

> > fifteen minutes, which includes walking

> > approximately 1.9 miles and several sets of isometric exercises,

> > a glucose of 120 or less yields a post exercise glucose reading of

> 160

> > plus

> > or minus 10 points, and I feel exhausted for a long time.

> > If I have a pre-exercise glucose level reading of 150 to 160, my post

> > exercise glucose level reading is usually around 75 plus or minus 10

> > points,

> > and I feel fairly good.

> > Do others experience this?

> > What are the explanations for these observations? Post this message

> to

> > other forums if you wish. I would really like to know.

> >

> >

> >

> >

> >

> >

> >

[Guest guest]

yes, good explanation Pat! Thanks!

Regards,

Questions looking for answers

> >

> >

> > What causes this?

> > First, I will note the following observation regarding my glucose

> > level reading and exercise: Prior to exercising for an hour and

> > fifteen minutes, which includes walking

> > approximately 1.9 miles and several sets of isometric exercises,

> > a glucose of 120 or less yields a post exercise glucose reading of

> 160

> > plus

> > or minus 10 points, and I feel exhausted for a long time.

> > If I have a pre-exercise glucose level reading of 150 to 160, my post

> > exercise glucose level reading is usually around 75 plus or minus 10

> > points,

> > and I feel fairly good.

> > Do others experience this?

> > What are the explanations for these observations? Post this message

> to

> > other forums if you wish. I would really like to know.

> >

> >

> >

> >

> >

> >

> >