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Old 03-17-2013
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Thyroid Three Types of Thyroid Hormones and Their Interconversion

Ok so there are 3 types of thyroid hormones:

- T4
- T3
- rT3 (reverse T3)


Who can tell me what enzymes convert these hormones to one another?

Also, what is reverse T3 exactly? (not mentioned in First Aid, and the levels can be tested when asked after supplementation of exogenous T3)

Oh, and what medications can block conversion from happening?
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Old 03-19-2013
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enzymes: deiodinases

reverse T3: an isomer, inactive form, converted from T3 by deiodinases

Conversion inhibitor: Propylthiouracil
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Old 03-20-2013
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T3-----> more active than T4
reverse t3 is inactive.

5'monoiodinase ----> coverts T4 to T3

5monoiodinase----> converts T4 to reverse t3


peripheral conversion is blocked by Dexamethasone (not too sure).

T4 is converted into T3 because it is more active form. and T4 is converted into T3 in stress conditions (eg. infections, increased cortisol levels, post-surgery). Because in stress body produces the stress hormones which lead to increased metabolism and loss of energy, so to conserve the energy sources T4 is converted into inactive form reverse-t3.



Correct me, iF I am wrong.
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