a crystalline hormone, CHINO, secreted by the thyroid gland, that influences the rate of general metabolic activity: used medically, esp. to treat hypothyroidism
See triiodothyronine in American Heritage Dictionary 4
(trīˌī-ōˌdō-thīˈrə-nēnˌ, -ī-ŏdˌō-)
noun
A thyroid hormone, C15H12I3NO4, similar to thyroxine but more potent, used in the treatment of hypothyroidism.