描述
Iodide is actively absorbed from the bloodstream and concentrated in the thyroid follicles. (If there is a deficiency of dietary iodine, the thyroid enlarges in an attempt to trap more iodine, resulting in goitre.) Via a reaction with the enzyme thyroperoxidase, iodine is covalently bound to tyrosine residues in the thyroglobulin molecules, forming monoiodotyrosine (MIT) and diiodotyrosine (DIT). Linking two moieties of DIT produces thyroxine. Combining one particle of MIT and one particle of DIT produces triiodothyronine.
The thyronamines function via some unknown mechanism to inhibit neuronal activity; this plays an important role in the hibernation cycles of mammals. One effect of administering the thyronamines is a severe drop in body temperature.
Both T3 and T4 are used to treat thyroid hormone deficiency (hypothyroidism). They are both absorbed well by the gut, so can be given orally. Levothyroxine, the most commonly used synthetic thyroxine form, is a stereoisomer of physiological thyroxine, which is metabolised more slowly and hence usually only needs once-daily administration. Natural desiccated thyroid hormones, which are derived from pig thyroid glands, are a "natural" hypothyroid treatment containing 20% T3 and traces of T2, T1 and calcitonin.
A group of metabolites derived from thyroxine and triiodothyronine via the peripheral enzymatic removal of iodines from the thyroxine nucleus. Thyronine is the thyroxine nucleus devoid of its four iodine atoms. [HMDB]
InChI标识符
InChI=1S/C15H15NO4/c16-14(15(18)19)9-10-1-5-12(6-2-10)20-13-7-3-11(17)4-8-13/h1-8,14,17H,9,16H2,(H,18,19)/t14-/m0/s1