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Old 08-31-2009, 07:55 AM   #4
javelina javelina is offline
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Re: Could synthroid be making me dizzy?

Interesting! I stand corrected. I looked it up too and you are right, there are iodine atoms in T4. I found this in an online encyclopedia:

Quote:
Thyroxine is produced by attaching iodine atoms to the ring structures of tyrosine molecules. Thyroxine (T4) contains four iodine atoms. Triiodothyronine (T3) is identical to T4, but it has one less iodine atom per molecule... Iodine is an essential trace element for life, the heaviest element commonly needed by living organisms, and the second-heaviest known to be used by any form of life (only tungsten, a component of a few bacterial enzymes, has a higher atomic number and atomic weight). Iodine's main role in animal biology is as constituents of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). These are made from addition condensation products of the amino acid tyrosine, and are stored prior to release in an iodine-containing protein called thyroglobulin. T4 and T3 contain four and three atoms of iodine per molecule, respectively. The thyroid gland actively absorbs iodide from the blood to make and release these hormones into the blood, actions which are regulated by a second hormone TSH from the pituitary. Thyroid hormones are phylogenetically very old molecules which are synthesized by most multicellular organisms, and which even have some effect on unicellular organisms.
Obviously I'm no chemist, but per your question, if you are allergic to iodine, if you were I don't think you would be alive, since iodine is an "essential trace element for life"

Quote:
The thyroid gland actively absorbs iodide from the blood to make and release these hormones into the blood, actions which are regulated by a second hormone TSH from the pituitary.
I do know that many people with autoimmune thyroid disease can't tolerate iodine suppliments or iodine-rich foods but we all need some of it (and it is in the soils and hence the foods grown in those soils as well as added to salt so we are always getting some of it, especially in non-iodine deficient countries like the US).
I think that since the thyroid gland actively absorbs iodine and this allows it to release hormones, it might enhance or cause more autoimmune attacks to add more iodine and make the thyroid yet more active. Just my pet theory. Everything I read about autoimmune thyroid treatment calls for supplimenting the thyroid hormones to the extent where the thyroid is less active or actually inactive so as to prevent it from being an immune target.