Creatine and the heart

[Guest guest]

With all of the discussion around creatine on the list, understanding that

creatine helps in the retention of water in muscle and, the heart being a

muscle, has there been any studies pro or con about this? Does the heart

muscle retain water as the result of creatine at all?

Carson Wood.

Westbrook ME USA.

[Guest guest]

Mechanism of action of Creatinine - The following may

help some understand how this supplement works.

Ralph Giarnella MD

Southington Ct USA

Creatine and Other Supplements

Pediatric Clinics of North America - Volume 54, Issue

4 (August 2007)  -  Copyright © 2007 W. B. Saunders

Company

Creatine and Other Supplements

 Lattavo, DOa, & #8727;

 Kopperud, MDb,c

D. , MD, MPH, FAAPc,d

Mechanism of action

Although the use of creatine as a

performance-enhancing substance seems to be a new

phenomenon, creatine originally was described in the

1830s by Chevreul; it has undergone extensive study

since that time. Creatine is a nonessential amino acid

that is formed in the liver by a two-step process from

arginine and glycine; it also is found in varying

amounts in different meats [35], [36]. Creatine is

taken up by muscle cells by way of a sodium-dependent

transporter [36]. Once in the cells, creatine is

believed to have multiple functions through which

supplementation may enhance exercise performance. All

of these major functions center around the following

reaction of the enzyme creatine kinase:

Creatine then gives rise to five major functions

within skeletal muscle cells [37].

The first of these functions of the “phosphocreatine

system” is to serve as a “temporal energy buffer”

within the cell. The main purpose is the direct

rephosphorylation of ATP from phosphocreatine as a

means of “buffering” against changes in ATP during

short-duration exercise [36]. This is corroborated by

the fact that there seems to be little difference in

total cell ATP in muscle cells whether they are

contracted or relaxed [38].

In addition to being an acute energy buffer for the

regeneration of ATP within the cell, it is generally

accepted that the phosphocreatine system serves as a

transport system for energy between sites of energy

production and sites of energy use. This is supported

most significantly by a surprising amount of evidence

regarding the compartmentation of creatine kinase

isoenzymes within the cell [37].

Not only does the phosphocreatine system give cells a

specialized system of energy buffer and energy

transport, it serves three other biochemical functions

within the cell.

The first of these is to buffer against an increase in

intracellular ADP, which prevents inhibition of

ATP-dependent processes and prevents a net loss of

adenine nucleotide pools by way of adenylate kinase

[37], [39].

The reaction also helps to prevent intracellular

acidosis during exercise by consuming hydrogen ions

[36].

Finally, the system plays an important role in

providing an appropriate ATP/ADP ratio in localized

areas of the cell. For example, in muscle cells, the

action of creatine kinase allows for a larger amount

of ATP at the myofibril, while providing a higher

amount of ADP at the mitochondria, which can then be

rephosphorylated to ATP by way of oxidative

phosphorylation [37].

Although the physiologic effects of creatine within

the body are important and likely play a vital role in

the effectiveness of creatine as a

performance-enhancing substance, there has been some

evidence that ingestion of exogenous creatine may have

other effects within the cell.

First of all, it is believed that ingestion of

creatine and uptake into cells increases water intake

into the cells by osmotic action [40]. Secondary to

this, there seems to be an increase in body mass after

ingestion of creatine, especially in young, healthy

men [36].

It also is theorized that the increase in

intracellular water may have the effect of decreasing

the breakdown of protein within the cell and possibly

also increasing protein synthesis within the cell

[41].

************

[36]  Terjung R., son P., Eichner R., et al:  The

American College of Sports Medicine roundtable on the

physiological and health effects of oral creatine

supplementation.  Med Sci Sports Exerc 32. (3):

706-717.2000;  Abstract

[37]  Wallimann T., Wyss M., Brdiczka D., et al: 

Intracellular compartmentation, structure and function

of creatine kinase isoenzymes in tissues with high and

fluctuating energy demands: the ‘phosphocreatine

circuit’ for cellular energy homeostasis.  Biochem

J 281. 21-40.1992;  Citation

[38]  Mommaerts W., Wallner A.:  The breakdown of

adenosine triphosphate in the contraction cycle of the

frog sartorius muscle.  J Phys 193. 343-357.1967; 

[39]  Iyengar M.R.:  Creatine kinase as an

intracellular regulator.  J Muscle Res Cell

Motil 5. 527-534.1984;  Abstract

[40]  Hultman D., Soderlund K., Timmons J.A., et al: 

Muscle creatine loading in men.  J Appl

Physiol 81. 232-237.1996;  Abstract

[41]  Haussinger D., Roth E., Lang F., et al: 

Cellular hydration state: an important determination

of protein catabolism in health and disease.

[Guest guest]

Mechanism of action of Creatinine - The following may

help some understand how this supplement works.

Ralph Giarnella MD

Southington Ct USA

Creatine and Other Supplements

Pediatric Clinics of North America - Volume 54, Issue

4 (August 2007)  -  Copyright © 2007 W. B. Saunders

Company

Creatine and Other Supplements

 Lattavo, DOa, & #8727;

 Kopperud, MDb,c

D. , MD, MPH, FAAPc,d

Mechanism of action

Although the use of creatine as a

performance-enhancing substance seems to be a new

phenomenon, creatine originally was described in the

1830s by Chevreul; it has undergone extensive study

since that time. Creatine is a nonessential amino acid

that is formed in the liver by a two-step process from

arginine and glycine; it also is found in varying

amounts in different meats [35], [36]. Creatine is

taken up by muscle cells by way of a sodium-dependent

transporter [36]. Once in the cells, creatine is

believed to have multiple functions through which

supplementation may enhance exercise performance. All

of these major functions center around the following

reaction of the enzyme creatine kinase:

Creatine then gives rise to five major functions

within skeletal muscle cells [37].

The first of these functions of the “phosphocreatine

system” is to serve as a “temporal energy buffer”

within the cell. The main purpose is the direct

rephosphorylation of ATP from phosphocreatine as a

means of “buffering” against changes in ATP during

short-duration exercise [36]. This is corroborated by

the fact that there seems to be little difference in

total cell ATP in muscle cells whether they are

contracted or relaxed [38].

In addition to being an acute energy buffer for the

regeneration of ATP within the cell, it is generally

accepted that the phosphocreatine system serves as a

transport system for energy between sites of energy

production and sites of energy use. This is supported

most significantly by a surprising amount of evidence

regarding the compartmentation of creatine kinase

isoenzymes within the cell [37].

Not only does the phosphocreatine system give cells a

specialized system of energy buffer and energy

transport, it serves three other biochemical functions

within the cell.

The first of these is to buffer against an increase in

intracellular ADP, which prevents inhibition of

ATP-dependent processes and prevents a net loss of

adenine nucleotide pools by way of adenylate kinase

[37], [39].

The reaction also helps to prevent intracellular

acidosis during exercise by consuming hydrogen ions

[36].

Finally, the system plays an important role in

providing an appropriate ATP/ADP ratio in localized

areas of the cell. For example, in muscle cells, the

action of creatine kinase allows for a larger amount

of ATP at the myofibril, while providing a higher

amount of ADP at the mitochondria, which can then be

rephosphorylated to ATP by way of oxidative

phosphorylation [37].

Although the physiologic effects of creatine within

the body are important and likely play a vital role in

the effectiveness of creatine as a

performance-enhancing substance, there has been some

evidence that ingestion of exogenous creatine may have

other effects within the cell.

First of all, it is believed that ingestion of

creatine and uptake into cells increases water intake

into the cells by osmotic action [40]. Secondary to

this, there seems to be an increase in body mass after

ingestion of creatine, especially in young, healthy

men [36].

It also is theorized that the increase in

intracellular water may have the effect of decreasing

the breakdown of protein within the cell and possibly

also increasing protein synthesis within the cell

[41].

************

[36]  Terjung R., son P., Eichner R., et al:  The

American College of Sports Medicine roundtable on the

physiological and health effects of oral creatine

supplementation.  Med Sci Sports Exerc 32. (3):

706-717.2000;  Abstract

[37]  Wallimann T., Wyss M., Brdiczka D., et al: 

Intracellular compartmentation, structure and function

of creatine kinase isoenzymes in tissues with high and

fluctuating energy demands: the ‘phosphocreatine

circuit’ for cellular energy homeostasis.  Biochem

J 281. 21-40.1992;  Citation

[38]  Mommaerts W., Wallner A.:  The breakdown of

adenosine triphosphate in the contraction cycle of the

frog sartorius muscle.  J Phys 193. 343-357.1967; 

[39]  Iyengar M.R.:  Creatine kinase as an

intracellular regulator.  J Muscle Res Cell

Motil 5. 527-534.1984;  Abstract

[40]  Hultman D., Soderlund K., Timmons J.A., et al: 

Muscle creatine loading in men.  J Appl

Physiol 81. 232-237.1996;  Abstract

[41]  Haussinger D., Roth E., Lang F., et al: 

Cellular hydration state: an important determination

of protein catabolism in health and disease.

[Guest guest]

Apparently there are no studies concerning the heart.

Read below.

Ralph Giarnella MD

Southington Ct USA

****************

Creatine and Other Supplements

Pediatric Clinics of North America - Volume 54, Issue

4 (August 2007)  -  Copyright © 2007 W. B. Saunders

Company

Creatine and Other Supplements

 Lattavo, DOa, & #8727;

 Kopperud, MDb,c

D. , MD, MPH, FAAPc,d

Creatine's effects on other creatine-containing

tissues, such as the brain, cardiac muscle, and

testes, are unknown [4].

[4]  Tokish J.M., Kocher M.S., Hawkins R.J.: 

Ergogenic aids: a review of basic science,

performance, side effects, and status in sports.  Am J

Sports Med 32. (6): 1543-1553.2004;  Abstract