| thyroid hormone | <endocrinology> Thyroxine and tri iodothyronine are hormones secreted by the thyroid gland in vertebrates. These iodinated aromatic amino acid compounds influence growth and metabolism and, in amphibia, metamorphosis. The hormone calcitonin which has hypocalcaemic effects is also of thyroid origin but is not usually classed with thyroxine and tri iodothyronine as a thyroid hormone. (18 Nov 1997) |
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| thyroid hormone aminotransferase | <enzyme> Chemical name: 3,5-dinitrotyrosine aminotransferase Registry number: EC 2.6.1.26 Synonym: triiodothyrone aminotransferase, triiodothyronine aminotransferase (26 Jun 1999) |
| thyroid hormone resistance syndrome | <syndrome> An inherited syndrome of peripheral resistance to thyroid hormones, transmitted as an autosomal recessive trait, characterised by increased serum concentrations of thyroxine and triiodothyronine, increased thyroid hormone binding ratio, and normal to slightly increased thyroid-stimulating hormone and its response to thyrotropin-releasing hormone. The affected persons are euthyroid to slightly hypothyroid. The absence of hypermetabolism and the presence of possible hypothyroidism indicate the existence of partial resistance to the peripheral action of thyroid hormone. (12 Dec 1998) |
| thyroid hormones | Chemical substances made by the thyroid gland which is located in the front of the neck. The thyroid gland uses iodine to make thyroid hormones. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body. The two most important thyroid hormones are thyroxine (t4) and triiodothyronine (T3). (12 Dec 1998) |
| thyroid ima artery | <anatomy, artery> An inconstant artery; origin, arch of aorta or brachiocephalic artery; distribution, thyroid gland. Synonym: arteria thyroidea ima, lowest thyroid artery, Neubauer's artery. (05 Mar 2000) |
| thyroid imaging | <radiology> Tc-99m pertechnetate 6 mCi, I-123 sodium iodide 200 - 400 uCi PO (12 Dec 1998) |
| thyroid insufficiency | Subnormal secretion of hormones by the thyroid gland. See: hypothyroidism. (05 Mar 2000) |
| thyroid lymph nodes | Nodes of the anterior deep cervical group located around the thyroid gland; they drain into the lateral deep cervical group. Synonym: nodi lymphatici thyroidei. (05 Mar 2000) |
| thyroid nodule | A small circumscribed mass of differentiated tissue associated with the thyroid gland. It can be pathogenic or non-pathogenic. The growth of nodules can lead to a condition of goiter, nodular. most nodules appear between the ages of 30 and 50 years and most are benign. (12 Dec 1998) |
| thyroid receptor antibody | A test that measures the amount of an antibody (thyroid stimulating antibody) which is directed against a receptor for TSH on the thyroid gland. This antibody acts like TSH and stimulates the thyroid to produce excessive amounts of thyroid hormone. The presence of this antibody generally indicates Grave's disease (hyperthyroidism). (27 Sep 1997) |
| thyroid releasing hormone | <endocrinology> Thyroid releasing hormone (TRH) is a byproduct of the hypothalamus and serves to stimulate the pituitary gland to produce thyroid stimulating hormone (TSH). TRH is produced by the hypothalamus when thyroid hormone (T3 and T4) blood levels are low. (27 Sep 1997) |
| thyroid scan | A picture taken of the thyroid gland after radioactive iodine is taken by mouth. (12 Dec 1998) |
| thyroid stimulating antibody | <endocrinology, immunology> Long acting thyroid stimulator is an autoantibody found in many cases of primary thyrotoxicosis which causes hyperplasia of the thyroid by undetermined mechanisms. Human thyroid stimulating immunoglobulin is a different antibody found in all or nearly all cases of primary thyrotoxicosis and may act by binding to the thyrotropin (TSH) receptor site, causing increased synthesis of thyroglobulin. (18 Nov 1997) |
| thyroid stimulating hormone | <endocrinology> Polypeptide hormone (28 kD), secreted by the anterior pituitary gland, that activates cyclic AMP production in thyroid cells leading to production and release of the thyroid hormones (T4 and T3). T4 and T3 blood levels feedback on the pituitary gland and decrease thyroid stimulating hormone production when T3 and T4 levels are high. (27 Sep 1997) |
| thyroid-stimulating hormone | thyroid stimulating hormone |