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Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Nov 7, 2008; 14(41): 6334-6338
Published online Nov 7, 2008. doi: 10.3748/wjg.14.6334
Ghrelin and gastric acid secretion
Koji Yakabi, Junichi Kawashima, Shingo Kato
Koji Yakabi, Junichi Kawashima, Shingo Kato, Department of Gastroenteology and Hepatology, Saitama Medical Center, Saitama Medical University, Kawagoe-city, Saitama 350-8550, Japan
Author contributions: Yakabi K is the main author and wrote the paper. Kawashima J and Kato S evaluated the references and discussed on the theme with Yakabi K. This review is the results of the discussion.
Correspondence to: Koji Yakabi, Department of Gastro-entorlogy and Hepatology, Saitama Medical Center, Saitama Medical School, 1821 Kamoda Tsujido-machi, Kawagoe-city, Saitama 350-8550, Japan. kjyakabi@saitama-med.ac.jp
Telephone: +81-49-228-3564 Fax: +81-49-2256649
Received: October 15, 2008
Revised: October 30, 2008
Accepted: November 6, 2008
Published online: November 7, 2008
Abstract

Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-induced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

Keywords: Ghrelin; Acid secretion; Vagal nerve; Vagotomy; Histamine; Histidine decarboxylase