Re: t4 storage-buildup in the blood

[Guest guest]

> In a message dated 3/16/2005 8:48:31 AM Eastern Standard Time,

> gnattygrl@y... writes:

>

> > T4 is actually what is

> > used in the brain - T3 cannot cross the blood brain barrier

>

> but i thought i had read - that the thyroid gland does produce

some T3 on its

> own...and that's why folks with psychiatric symptoms do well on

armour -

> because it has T3 that can be used by the brain.

> anyone know more about this - about the brain and using straight

T3 as

> opposed to conversion. from some reason, i thought the brain

could not convert.

> cindi

Yep, that's what I thought as well - however that's now how it

works. At least according to Dr. Dommisse's research. From the

paper I sent to Janie to post in the files section:

" The T4 hormone merely serves as a pro_hormone or pre-hormone, with

the possible exception of brain-function, which may require a

significant amount of T4 for its optimal function because T4 is

transported through the choroid plexus and T3 is not (Whybrow,

1991; Whybrow, 1994). "

[Guest guest]

>

> I know when I was first

> > diagnosed I was put on only T4 meds and told I wouldn't notcie

> > anything for weeks, because it's so slow acting. I noticed a

> > difference the next day; no more constant headaches, the brain

fog

> > lifted a little and the dizziness stopped.

>

> This is a very interesting subjective observation which seems to

> confirm the T4 action to T3 in the brain. Glad you shared it.

>

> Janie

Janie, it was a surprize, as you can imagine. What's more, when I

was originally diagnoses my FT4 was really low (bottom 1/4), but my

FT3 was in the upper 3rd. I couldnt remember my phone number, my

postal code, where I left my keys... I was also exahusted and

losing hair but the brain related symptoms where the most

devastating, and the first to clear up on the synthroid.

[Guest guest]

>

> I know when I was first

> > diagnosed I was put on only T4 meds and told I wouldn't notcie

> > anything for weeks, because it's so slow acting. I noticed a

> > difference the next day; no more constant headaches, the brain

fog

> > lifted a little and the dizziness stopped.

>

> This is a very interesting subjective observation which seems to

> confirm the T4 action to T3 in the brain. Glad you shared it.

>

> Janie

Janie, it was a surprize, as you can imagine. What's more, when I

was originally diagnoses my FT4 was really low (bottom 1/4), but my

FT3 was in the upper 3rd. I couldnt remember my phone number, my

postal code, where I left my keys... I was also exahusted and

losing hair but the brain related symptoms where the most

devastating, and the first to clear up on the synthroid.

[Guest guest]

>

> OK, a big gold star on your report card for finding these

> interesting research articles.

>

> As far as the statement " The in vivo T4 to T3 conversion, as a

> function of weight, accounted for 21% of cerebellum needs and 43%

of

> brain needs. The rest was provided by T3 uptake. " ---if only 21% of

> cerebellum's needs and 43% of the brain's needs come from the

> conversion, it also shows the great need for the " direct " T3.

>

> Because if I am reading it right, that would mean that 79% of the

> cerebellum's needs and 57% of the brains needs are for the direct

T3.

>

> Makes you wonder once again why any doc could defend the practice

of

> giving a patient ONLY T4-only meds........

>

> Janie

>

>

> > http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

> cmd=Retrieve&db=PubMed&list_uids=11094382&dopt=Abstract

> >

I cring when I hear about how someone is doing 'great' on just

synthroid. I also cring when I hear how someone is doing 'great' on

cytomel alone. We need them both - otherwise our bodies wouldn't

make them.

ONTH, The problem with these studies is you can find one to back up

just about anything (I once found one that wherein athsma inhallers

were made out of chocolate to ensure they were used):

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=6470136

In hypothyroidism, the Cx is protected by an increase in the

efficiency of T4 to T3 conversion and a prolong residence time of T3

in the tissue, whereas the Cm is protected only by the latter.

Because of the large fraction of the T3 produced locally and the

active turnover rate of T3 in the brain, reductions in T3 removal

rate are of utmost importance for T3 homeostasis in these tissues.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=4017962

Although there were no regional differences between the total T3

levels in the brain, the relative contribution of locally converted

T3(T4) was 65% in the cerebral cortex and only 22% in the spinal cord

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3766050

From these data the concentrations of T4, total T3 and T3 derived

from local T4 to T3 conversion (LcT3(T4)) in tissue could be

calculated. The relative mean contribution of LcT3(T4) to the total

T3 in Cerebral cotex (75%), thymus (31%), testis (43%) and brown

adipose tissue (65%) from hypothyroid rats was higher than that

determined for euthyroid animals (66%, 19%, 29% and 27%,

respectively). The reverse was found for the liver (15% vs 39%).