thyroxin
(thy-ROK-sin)
A hormone that is made by the thyroid gland and contains iodine. Thyroxin increases the rate of chemical reactions in cells and helps control growth and development. Thyroxin can also be made in the laboratory and is used to treat thyroid disorders. Also called L-3,5,5’-tetraiodothyronine, T4, and thyroxine.