thyroxine /θaɪˈrɒksɪn/ (also thyroxin)

• 1. 

  N the principal hormone produced by the thyroid gland: it increases the metabolic rate of tissues and also controls growth, as in amphibian metamorphosis. It can be synthesized or extracted from the thyroid glands of animals and used to treat hypothyroidism. Chemical name: tetra-iodothyronine; formula: C15H11I4NO4 甲状腺素