| 释义 |
calcitonin, n. Physiol. and Biol.
Brit. |ˌkalsɪˈtəʊnɪn|, U.S. |ˌkælsəˈtoʊnən|
[‹ calci- (in calcium n.) + tone n. + -in suffix1 (see quot. 1962).]
A polypeptide hormone secreted by the parafollicular cells of the thyroid in mammals and by the ultimobranchial body in other vertebrates, which lowers the levels of calcium and phosphate in the blood by promoting the absorption and retention of calcium in bone, and by increasing the rate of excretion of calcium and phosphate in urine.
1961D. H. Copp et al. in Proc. Canad. Federation Biol. Sci. 4 17/2 The name ‘calcitonin’ is suggested for this humoral substance to distinguish it from the regular parathyroid hormone. 1962D. H. Copp et al. in Endocrinology 70 648/2 Since this new hormone is involved in the regulation of the normal ‘tone’ of calcium in the body fluids, we have suggested that it be named ‘calcitonin’. 1967Canad. Med. Assoc. Jrnl. 97 941/1 Since the so-called parafollicular or light cells of the thyroid gland..are probably derived from ultimobranchial rather than thyroid tissue, the original name calcitonin seems preferable to thyrocalcitonin. 1980Proc. National Acad. Sci. U.S.A. 77 4444/1 This clonal cDNA was used as a probe to assay the expression of the calcitonin gene. 1981R. N. Hardy Endocrine Physiol. viii. 90 Calcitonin serves to lower Ca2+ concentration in blood by increasing bone calcium stores. 1991D. J. Weatherall New Genetics & Clin. Pract. (ed. 3) xi. 336 The calcitonin gene generates two messenger RNAs, one encoding the precursor of a novel neuropeptide, the other the precursor of the hormone calcitonin; the neuropeptide predominates in the nervous system. 1996Fibromyalgia Times Fall 7/2 There are now alternatives for the treatment of osteoporosis. These include a nasal spray—calcitonin (Miacalcin) and a tablet—alendronate (Fosamax).
Compounds. calcitonin gene-related peptide n. a neuropeptide produced esp. in the hypothalamus, which acts as a neuromodulator, and is a potent vasodilator and hypotensive agent.
1982Nature 15 July 240 Alternative processing of RNA transcripts from the calcitonin gene results in the production of distinct mRNAs encoding the hormone calcitonin or a predicted product referred to as *calcitonin gene-related peptide (CGRP). 1990Sci. News Apr. 244/2 Researchers have now found that an experimental drug—calcitonin-gene-related peptide—temporarily reversed symptoms caused by reduced blood flow to the brain. 2001Jrnl. Musculoskeletal & Neuronal Interactions 2 137 The innervation of callus reveals an extensive distribution of sensory fibers containing a calcitonin gene-related peptide, a neuropeptide with potent vasodilatory actions. |