L-3,5,5’-tetraiodothyronine
(...TEH-truh-i-oh-doh-THY-roh-neen)
A hormone that is made by the thyroid gland and contains iodine. L-3,5,5’-tetraiodothyronine increases the rate of chemical reactions in cells and helps control growth and development. L-3,5,5’-tetraiodothyronine can also be made in the laboratory and is used to treat thyroid disorders. Also called T4, thyroxin, and thyroxine.