why gallstones and thryoid is interlinked---fyi

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Textbook of Endocrinology 9th ed. page 402

Thyroidal T4 must be converted to T3 to produce its effects. This

conversion may take place in the liver, kidney and thyroid catalyzed

by either the propylthiouracil-sensitive iodothyronine 5'-deiodinase

or the propylthiouracil-insensitive 5'-deiodinase

Endocrinology 5th edition 1999 by Mac Hadley (Pre-Med Text) page 324

The active form of thyroid hormone, triiodothyronine (T3), is

produced by deiodination of thyroxine (T4) by the enzymes T(4)5'-

deiodinase (5'-D) types I and II. Type I T(4)5-deiodinase is found

predominatly IN THE LIVER AND KIDNEYS; it's action is responsible for

the production of two-thirds of the total T3 in the body. Type II T

(4)5 " -deiodinase is responsible for most of the T3 found in the

pituitary, the brain and brown fat.

Endocrinology and Metabolism 2001 edition page 32

5'-Deiodinase removes an iodine atom from the phenylic ring of T4 or

rT3. As this process generates T3 from T4, this enzyme activates

thyroid hormones.

Type I 5'-deiodinase is mostly expressed in the liver and kidney. It

is also present at lower concentrations in the CNS, in the adipose

tissue, and in fibroblasts. Because of the high level of 5'-

deiodinase present in the LIVER and because of the liver size and

ability to concentrate T4, approximately 70% of the T3 production

originates from the liver

http://www.anapsid.org/cnd/diagnosis/gordontalk.html

Treating thyroid deficiency isn't always as easy as it seems when

looking at disease-model medicine. In most people, their bodies

convert the T4 they take into T3 just fine. For the others, " we may

need to give them T4 and T3, or just T3, to see if we can fix the

problem in the liver that is preventing their body from being able to

do the conversion of endogenous T4 into T3. "

The disease-based model ignores the fact that all chemicals that

enter the body - through the mouth, respiratory tract, and skin -

have to be rendered inert by the liver. In addition, the liver has to

deal with all of the hormones produced by our bodies.

http://www.thyroidmanager.org/Chapter3/3b-text.htm

About 80% of circulating T3 is produced outside the thyroid gland by

peripheral conversion of T4 into T3 and 20% is directly secreted by

the thyroid gland. The liver plays an important role in this extra-

thyroidal production of T3 (1)

A patient has been described in whom plasma T3 production was found

to be low, while T4 production was normal (8). T4 transport into the

liver was decreased, but it was normal into non-hepatic tissues. No

abnormalities were found with regard to T3 transport into tissues.

Deiodinase activity in the liver, measured using thyroid hormone

tracer kinetics, was normal. From these data it was concluded that

the low T3 production rate was caused by the inhibition of T4

transport into the liver. In other words, uptake of T4 into the liver

may have a regulatory role in plasma T3 production and thus the

regulation of thyroid hormone activity at the tissue level (8).

http://www.jpteez.com/html/thyroid2.html

....,because the liver is the primary site of conversion of T4 to T3.

The dosage of anticonvulsant required for seizure control may be able

to bel lowered or even discontinued. It may also offset any adverse

effects of anticonvulsants on liver metabolism which could impair

hepatocellular conversion of T4 to T3.

http://www.postgradmed.com/issues/1999/04_99/camacho.htm

Triiodothyronine (T3), which is three to five times more potent than

T4, is produced both by the thyroid gland and by peripheral

conversion of T4 to T3. Conversion involves the 5'-deiodinase enzyme

and occurs mostly in the liver and kidney.

http://www.altsupportthyroid.org/t3/t3medrefs2.php

As hypothyroid patients are usually unable to convert inactive T4

into active T3, owing to a lack of 5' -deiodinase in the liver and

kidneys, the administration of T4 can eventually correct the serum

TSH level, but rarely provides the patient with the T3 needed to be

relieved of his symptoms.

http://village.vossnet.co.uk/c/crina/pag-liver.html

The liver converts the thyroid hormone thyroxine (T4) into its more

active form tri-iodothyronine (T3).

http://www.antibodyassay.com/testinfo/thyroid_24_urine.htm

The enzyme, deiodinase, converts T4 into T3. This conversion occurs

primarily in the liver and kidneys.