Search results
Results from the WOW.Com Content Network
At the cellular level, T 3 is the body's more active and potent thyroid hormone. [2] T 3 helps deliver oxygen and energy to all of the body's cells, its effects on target tissues being roughly four times more potent than those of T 4. [2] Of the thyroid hormone that is produced, just about 20% is T 3, whereas 80% is produced as T 4.
3,3'-Diiodothyronine, also known as 3,3'-T 2, is a metabolite of thyroid hormone. It is formed from the breakdown of triiodothyronine . Levels can be affected in certain disease states.
The pituitary gland secretes thyrotropin (TSH; Thyroid Stimulating Hormone) that stimulates the thyroid to secrete thyroxine (T4) and, to a lesser degree, triiodothyronine (T3). The major portion of T3, however, is produced in peripheral organs, e.g. liver, adipose tissue, glia and skeletal muscle by deiodination from
Thyroid hormones lead to heat generation in humans. However, the thyronamines function via some unknown mechanism to inhibit neuronal activity; this plays an important role in the hibernation cycles of mammals and the moulting behaviour of birds. One effect of administering the thyronamines is a severe drop in body temperature.
Liothyronine is a manufactured form of the thyroid hormone triiodothyronine (T 3). [2] It is most commonly used to treat hypothyroidism and myxedema coma. [2] It can be taken by mouth or by injection into a vein. [2] Side effects may occur from excessive doses. [2]
Inactivation of thyroid hormones occurs by removal of an iodine atom on the inner ring, which converts thyroxine to the inactive reverse triiodothyronine (rT 3), or which converts the active triiodothyronine to diiodothyronine (T 2). The major part of thyroxine deiodination occurs within the cells. Deiodinase 2 activity can be regulated by ...
Three related isoforms, deiodinase type I, II, and III, contribute to activation and inactivation of the initially released hormone precursor T 4 into T 3 (triiodothyronine) or rT 3 (reverse triiodothyronine) in target cells. The enzymes catalyze a reductive elimination of iodine (the different isoforms attack different thyronine positions ...
The biological half-life of iodine differs between the various organs of the body, from 100 days in the thyroid, to 14 days in the kidneys and spleen, to 7 days in the reproductive organs. Typically the daily urinary elimination rate ranges from 100 to 200 μg/L in humans. [ 75 ]