tetraiodothyronine


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Related to tetraiodothyronine: thyroxine

thyroxine

 (T4) [thi-rok´sin]
a thyroid hormone that contains iodine and is a derivative of the amino acid tyrosine, occurring naturally as l-thyroxine; its chemical name is tetraiodothyronine. It is formed and stored in the thyroid follicles as thyroglobulin and released from the gland by the action of a proteolytic enzyme. It is deiodinated in peripheral tissues to form triiodothyronine (T3), which has a greater biological activity.



Thyroxine acts as a catalyst in the body and influences a great variety of effects, including metabolic rate (oxygen consumption); growth and development; metabolism of carbohydrates, fats, proteins, electrolytes, and water; vitamin requirements; reproduction; and resistance to infection. Pharmaceutical preparations of thyroxine, extracted from animals or made synthetically, are called levothyroxine.
free thyroxine the fraction of thyroxine in the serum that is not bound to a binding protein.

tetraiodothyronine

See thyroxine.

tetraiodothyronine

Thyroxin, see T4.

tetraiodothyronine

thyroxine; see thyroid hormones. Called also T4.
References in periodicals archive ?
The tyrosines are iodinated at one (monoiodotyrosine) or two (diiodotyrosine) sites and then coupled to form the active thyroid hormones, tetraiodothyronine or thryoxine ([T.
The only confirmed function of iodine is as an essential substrate for the synthesis of thyroid hormones, tetraiodothyronine (thyroxin or [T.
An elevated serum TSH level, coupled with low serum free or total tetraiodothyronine (T4) concentration, is diagnostic of primary hypothyroidism, regardless of etiology.