Re: Sheila only T4 can cross the blood-brain barrier?

[Guest guest]

That's awful Sheila -- sheesh -- so sorry for your friends troubles.

Please take care of yourself--this is so stressful!!!

Wish I could help you with the blood-brain barrier question!

xoxxo

only T4 can cross the blood-brain barrier?

Okay, i'm trying to find that article i must have read about 6

months ago...I know i read somewhere that T3 can't cross the blood-

brain barrier...didn't I?

What do you guys make of this one...is that was this is trying to

say? i can't make sense of anything right now.

i can't think right now. A friend a work is going through a hard

time. she found her 43 year old husband dead in bed. he had a

massive heart attack. anyway, it's really upset me a lot and i can't

think straight. sheila

http://www.kb.u-psud.fr/kb/english/research/inserm/umrs488.htm

2.2.6 Thyroid hormones and nervous regeneration

Steroids are not the only hormones that play an important role in

the processes of regeneration. For a long time it was thought that

the functions of the thyroid hormones were limited to the

development of the brain and the peripheral nerves. However, recent

work suggests that thyroid hormones continue to play an important

role in the functioning of the adult nervous system (memory,

adaptation to stress, antidepressive effects...). Above all after a

nervous lesion they may be able to accelerate regeneration

processes. A second important concept is suggested by our work :

triiodothyronine (T3), which is the most biologically active thyroid

hormone, is formed locally in the nervous system and its levels are

controlled by the activities of two deiodases: D2, which converts

circulating thyroxine (T4) to T3, and D3 which inactivates both T4

and T3.

We have just seen that after lesion of the sciatic nerve, the

expression of proteins implicated in steroid synthesis, such as the

PBR and 3b-HSD, is regulated by axonal signals. We have recently

shown that the expression of the thyroid hormone deiodases, D2 and

D3, is induced only a few hours after lesion of the nerve. When

there is regeneration, as in the case of a cryolesion, the induction

is transitory. On the other hand, in the case of a lesion by

section, when the fibers cannot regenerate, the levels of the D2 and

D3 mRNAs remain high for several weeks, preferentially on the distal

side but also on the proximal side (Neuroscience, in press). In

muscle, D2 is transiently induced at the moment of its innervation.

All these observations suggest that the local regulation of T3 is

important for an efficient regeneration process. Unlike PROG, which

is synthesized in Schwann cells, the conversion of T4 to T3 takes

place in the fibroblasts of the nerve's protective sheath. D3 is

present and active both in the sheath and inside the nerve.

Experiments are now planned to show the functional role of the

deiodases in the regeneration of peripheral nerves.

[Guest guest]

thanks, ...you know besides hurting so much for her, it also brings that

mortality issue smack dab center stage...know what i mean...can't just push it

aside. So i starting working on an art project last night to help me cope with

those feelings. I also wrote a poem. Expressive therapy is best way for me to

deal with feelings...

If i don't sleep when i get back home, i'm gonna work some more on that project

& dedicate it to my friend. it will help me feel better.

take care, ! Hugs, sheila

Hodgson <suser@...> wrote:

That's awful Sheila -- sheesh -- so sorry for your friends troubles.

Please take care of yourself--this is so stressful!!!

Wish I could help you with the blood-brain barrier question!

xoxxo

only T4 can cross the blood-brain barrier?

Okay, i'm trying to find that article i must have read about 6

months ago...I know i read somewhere that T3 can't cross the blood-

brain barrier...didn't I?

What do you guys make of this one...is that was this is trying to

say? i can't make sense of anything right now.

i can't think right now. A friend a work is going through a hard

time. she found her 43 year old husband dead in bed. he had a

massive heart attack. anyway, it's really upset me a lot and i can't

think straight. sheila

http://www.kb.u-psud.fr/kb/english/research/inserm/umrs488.htm

2.2.6 Thyroid hormones and nervous regeneration

Steroids are not the only hormones that play an important role in

the processes of regeneration. For a long time it was thought that

the functions of the thyroid hormones were limited to the

development of the brain and the peripheral nerves. However, recent

work suggests that thyroid hormones continue to play an important

role in the functioning of the adult nervous system (memory,

adaptation to stress, antidepressive effects...). Above all after a

nervous lesion they may be able to accelerate regeneration

processes. A second important concept is suggested by our work :

triiodothyronine (T3), which is the most biologically active thyroid

hormone, is formed locally in the nervous system and its levels are

controlled by the activities of two deiodases: D2, which converts

circulating thyroxine (T4) to T3, and D3 which inactivates both T4

and T3.

We have just seen that after lesion of the sciatic nerve, the

expression of proteins implicated in steroid synthesis, such as the

PBR and 3b-HSD, is regulated by axonal signals. We have recently

shown that the expression of the thyroid hormone deiodases, D2 and

D3, is induced only a few hours after lesion of the nerve. When

there is regeneration, as in the case of a cryolesion, the induction

is transitory. On the other hand, in the case of a lesion by

section, when the fibers cannot regenerate, the levels of the D2 and

D3 mRNAs remain high for several weeks, preferentially on the distal

side but also on the proximal side (Neuroscience, in press). In

muscle, D2 is transiently induced at the moment of its innervation.

All these observations suggest that the local regulation of T3 is

important for an efficient regeneration process. Unlike PROG, which

is synthesized in Schwann cells, the conversion of T4 to T3 takes

place in the fibroblasts of the nerve's protective sheath. D3 is

present and active both in the sheath and inside the nerve.

Experiments are now planned to show the functional role of the

deiodases in the regeneration of peripheral nerves.

[Guest guest]

Remember back in May a school mate of my son's also lost his father

at 49--I offered to help her with finances--decisions ect. So that is

what I have been doing to help her. Anything you can do with this

person will make you feel better and be able to handle their loss.

Even if you take her out to lunch--or call. Anything to help them.

tina

> That's awful Sheila -- sheesh -- so sorry for your friends

troubles.

>

> Please take care of yourself--this is so stressful!!!

>

> Wish I could help you with the blood-brain barrier question!

>

> xoxxo

> only T4 can cross the blood-brain

barrier?

>

>

> Okay, i'm trying to find that article i must have read about 6

> months ago...I know i read somewhere that T3 can't cross the

blood-

> brain barrier...didn't I?

>

> What do you guys make of this one...is that was this is trying to

> say? i can't make sense of anything right now.

>

> i can't think right now. A friend a work is going through a hard

> time. she found her 43 year old husband dead in bed. he had a

> massive heart attack. anyway, it's really upset me a lot and i

can't

> think straight. sheila

>

> http://www.kb.u-psud.fr/kb/english/research/inserm/umrs488.htm

>

>

>

> 2.2.6 Thyroid hormones and nervous regeneration

>

> Steroids are not the only hormones that play an important role in

> the processes of regeneration. For a long time it was thought

that

> the functions of the thyroid hormones were limited to the

> development of the brain and the peripheral nerves. However,

recent

> work suggests that thyroid hormones continue to play an important

> role in the functioning of the adult nervous system (memory,

> adaptation to stress, antidepressive effects...). Above all after

a

> nervous lesion they may be able to accelerate regeneration

> processes. A second important concept is suggested by our work :

> triiodothyronine (T3), which is the most biologically active

thyroid

> hormone, is formed locally in the nervous system and its levels

are

> controlled by the activities of two deiodases: D2, which converts

> circulating thyroxine (T4) to T3, and D3 which inactivates both

T4

> and T3.

>

> We have just seen that after lesion of the sciatic nerve, the

> expression of proteins implicated in steroid synthesis, such as

the

> PBR and 3b-HSD, is regulated by axonal signals. We have recently

> shown that the expression of the thyroid hormone deiodases, D2

and

> D3, is induced only a few hours after lesion of the nerve. When

> there is regeneration, as in the case of a cryolesion, the

induction

> is transitory. On the other hand, in the case of a lesion by

> section, when the fibers cannot regenerate, the levels of the D2

and

> D3 mRNAs remain high for several weeks, preferentially on the

distal

> side but also on the proximal side (Neuroscience, in press). In

> muscle, D2 is transiently induced at the moment of its

innervation.

> All these observations suggest that the local regulation of T3 is

> important for an efficient regeneration process. Unlike PROG,

which

> is synthesized in Schwann cells, the conversion of T4 to T3 takes

> place in the fibroblasts of the nerve's protective sheath. D3 is

> present and active both in the sheath and inside the nerve.

> Experiments are now planned to show the functional role of the

> deiodases in the regeneration of peripheral nerves.

>

>

>

>

>

>

[Guest guest]

Thanks, Tina! I'm getting ready to call her before I go into work. she is such a

sweet person...always smiling...so very much in love...like me. my heart is

still aching for her. I worked out some of my feelings with a poem and piece of

art i dedicated to her. i struggled with it all last night and today after work

but finally achieved what i wanted. I will show it to her when she's ready.

well, getting ready to call her...bracing myself...thanks! hugs, sheila

tina83862 <tina83862@...> wrote:

Remember back in May a school mate of my son's also lost his father

at 49--I offered to help her with finances--decisions ect. So that is

what I have been doing to help her. Anything you can do with this

person will make you feel better and be able to handle their loss.

Even if you take her out to lunch--or call. Anything to help them.

tina

> That's awful Sheila -- sheesh -- so sorry for your friends

troubles.

>

> Please take care of yourself--this is so stressful!!!

>

> Wish I could help you with the blood-brain barrier question!

>

> xoxxo

> only T4 can cross the blood-brain

barrier?

>

>

> Okay, i'm trying to find that article i must have read about 6

> months ago...I know i read somewhere that T3 can't cross the

blood-

> brain barrier...didn't I?

>

> What do you guys make of this one...is that was this is trying to

> say? i can't make sense of anything right now.

>

> i can't think right now. A friend a work is going through a hard

> time. she found her 43 year old husband dead in bed. he had a

> massive heart attack. anyway, it's really upset me a lot and i

can't

> think straight. sheila

>

> http://www.kb.u-psud.fr/kb/english/research/inserm/umrs488.htm

>

>

>

> 2.2.6 Thyroid hormones and nervous regeneration

>

> Steroids are not the only hormones that play an important role in

> the processes of regeneration. For a long time it was thought

that

> the functions of the thyroid hormones were limited to the

> development of the brain and the peripheral nerves. However,

recent

> work suggests that thyroid hormones continue to play an important

> role in the functioning of the adult nervous system (memory,

> adaptation to stress, antidepressive effects...). Above all after

a

> nervous lesion they may be able to accelerate regeneration

> processes. A second important concept is suggested by our work :

> triiodothyronine (T3), which is the most biologically active

thyroid

> hormone, is formed locally in the nervous system and its levels

are

> controlled by the activities of two deiodases: D2, which converts

> circulating thyroxine (T4) to T3, and D3 which inactivates both

T4

> and T3.

>

> We have just seen that after lesion of the sciatic nerve, the

> expression of proteins implicated in steroid synthesis, such as

the

> PBR and 3b-HSD, is regulated by axonal signals. We have recently

> shown that the expression of the thyroid hormone deiodases, D2

and

> D3, is induced only a few hours after lesion of the nerve. When

> there is regeneration, as in the case of a cryolesion, the

induction

> is transitory. On the other hand, in the case of a lesion by

> section, when the fibers cannot regenerate, the levels of the D2

and

> D3 mRNAs remain high for several weeks, preferentially on the

distal

> side but also on the proximal side (Neuroscience, in press). In

> muscle, D2 is transiently induced at the moment of its

innervation.

> All these observations suggest that the local regulation of T3 is

> important for an efficient regeneration process. Unlike PROG,

which

> is synthesized in Schwann cells, the conversion of T4 to T3 takes

> place in the fibroblasts of the nerve's protective sheath. D3 is

> present and active both in the sheath and inside the nerve.

> Experiments are now planned to show the functional role of the

> deiodases in the regeneration of peripheral nerves.

>

>

>

>

>

>