A therapeutic formulation of the primary physiologically active form of endogenous thyroid hormone. In vivo, triiodothyronine enters the nucleus and binds to nuclear thyroid hormone receptors that subsequently bind to thyroid response elements (TREs) located in target genes. Receptor binding by triiodothyronine in combination with recruited coactivators results in maximal transcriptional activation after binding to TREs; in general, binding of thyroid hormone receptor alone to TREs leads to repression of gene transcription (NCI04)

(triiodothyronine) A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.

(triiodothyronine) A thyroid hormone containing 3 iodine atoms generally synthesized from levothyroxine, and has greater biological activity.

(triiodothyronine) One of the thyroid hormones; an organic iodine containing compound secreted in small amounts by the thyroid gland; most circulating triiodothyroinine is produced by the deiodination of thyroxine in the peripheral tissues.

(triiodothyronine) One of two types of major thyroid hormone manufactured by the thyroid gland. It contains three iodine atoms. Also known as T3.