Ghrelin and gastric acid secretion.
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.
Yakabi
Koji
K
Department of Gastroentorlogy and Hepatology, Saitama Medical Center, Saitama Medical University, 1821 Kamoda Tsujido-machi, Kawagoe-city, Saitama 350-8550, Japan. kjyakabi@saitama-med.ac.jp
Kawashima
Junichi
J
Kato
Shingo
S
D000818:Animals; D015738:Famotidine / Q000494:pharmacology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D005755:Gastrins / Q000378:metabolism; D054439:Ghrelin / Q000378:metabolism*; D006632:Histamine / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006636:Histamine Release; D006640:Histidine Decarboxylase / Q000378:metabolism; D006801:Humans; D013270:Stomach / Q000187:drug effects / Q000294:innervation; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology
D005755:Gastrins; D054439:Ghrelin; D006635:Histamine H2 Antagonists; D015738:Famotidine; D006632:Histamine; D006640:Histidine Decarboxylase