an amino acid hormone that contains iodine and is secreted by the thyroid gland with thyroxine, to which it has a similar action. Formula: C15H12I3NO4
Word origin
C20: from tri- + iodo- + thyro- + -ine2
triiodothyronine in American English
(traɪˌaɪədoʊˈθaɪrəˌnin)
noun
a crystalline hormone, C15H12I3NO4, secreted by the thyroid gland, that influences the rate of general metabolic activity: used medically, esp. to treat hypothyroidism