A hormone produced by the thyroid gland.
Chemicals produced in the thyroid gland and released directly into the bloodstream by the thyroid. There are two thyroid hormones contained in the follicles of the gland in combination with the protein thyroglobulin. The first is thyroxine and is composed of the amino acid tyrosine containing four iodine atoms. The other thyroid hormone is triiodothyronine (or T3) and is made up of tyrosine with three iodine atoms.
An iodine-containing substance, synthesized and secreted by the thyroid gland, that is essential for normal metabolic processes and mental and physical development. There are two thyroid hormones, triiodotyrosine and thyroxine. Lack of these hormones gives rise to cretinism in infants and myxedema in adults. Excessive production of thyroid hormones gives rise to thyrotoxicosis.
Either of two hormones, thyroxine (T4) or triiodothyronine (T3, secreted by the follicles of the thyroid gland. The hormones act on receptors in tissues throughout the body to increase the production of cellular proteins, the metabolic rate, and the activities of the sympathetic nervous system. Deficiency of thyroid hormone produces clinical hypothyroidism; excess causes hyperthyroidism.
The thyroid gland produces three hormones: thyroxine (T4) and triiodothyronine (T3), which control metabolism, along with calcitonin, which helps manage the body’s calcium levels.