| gastrin | <hormone, protein> A group of peptide hormones secreted by the mucosal gut lining of some mammals in response to mechanical stress or high pH. When there is food in the stomach, these cells secrete gastrin. Gastrin then stimulates the stomach parietal cells to produce hydrochloric acid. Normally, as stomach pH lowers, gastrin secretion decreases. Gastrin blood levels can be determined to be elevated in conditions such as Zollinger-Ellison syndrome and pernicious anaemia. Several different gastrins have been identified, human gastrin I has 16 amino acids (2116 D). Gastrin is competitively inhibited by cholecystokinin. (05 Jan 1998) |
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| gastrin-releasing peptide | <hormone> A regulatory peptide (27 amino acids) thought to be the mammalian equivalent of bombesin. It elicits gastrin release and regulates gastric acid secretion and motor function. It causes bronchoconstriction and vasodilation in the respiratory tract and stimulates the growth and mitogenesis of cells in culture. Once released from nerves in the antrum of the stomach, the neuropeptide stimulates release of gastrin from the g cells. Chemical name: Gastrin-releasing peptide (12 Dec 1998) |
| gastrinase | <enzyme> Highly specific for the 34 amino acid gastrin Registry number: EC 3.4.99.- Synonym: gastrin-34 protease, gastrin-34 degrading enzyme (26 Jun 1999) |
| gastrinoma | <oncology, tumour> A tumour (gastrinoma) of the pancreatic islet cells that results in an over production of gastric acid, leading to fulminant ulceration of the oesophagus, stomach, duodenum and jejunum. Gastrinomas may also occur in the stomach, duodenum, spleen and regional lymph nodes. Treatment includes the use of H2 antagonists (for example cimetidine, ranitidine). Surgical excision of the tumour is curative in approximately 25% of patients. (27 Sep 1997) |
| gastrins | A family of gastrointestinal peptide hormones that excite the secretion of gastric juices. They may also occur in the central nervous system where they are presumed to be neurotransmitters. (12 Dec 1998) |