STUDIES ON MOTILIN RELEASE AND ITS MECHANISM IN NORMAL SUBJECTS AND PATIENTS WITH PEPTIC ULCER

Abstract

Motilin release in response to various factors and its mechanism were studied in normal subjects and patients with peptic ulcer by various tests and in vitro experiments using a perifusion system. The ingestion of a meat soup, protein and fat elevated plasma motilin levels as well as duodenal acidification, but oral glucose and insulin-induced hypoglycemia significantly lowered them. The untreated patients with peptic ulcer revealed a similar pattern of motilin release to that of normal subjects after the meat soup ingestion, insulininduced hypoglycemia and duodenal acidification. The postvagotomy patients showed a decrease in plasma motilin during the insulin-induced hypoglycemia.
The perifusion experiments demonstrated that motilin release from human duodenal mucosa into the perfusate was markedly stimulated by pH 2 solution and 15mM taurocholate, but not affected by the perifusion of glucose, fatty acid, amino acid, insulin and glucagon. Somatostatin inhibited motilin release from human duodenal mucosa.
These results indicate that motilin release induced by meal ingestion depend upon the balance of food components and that in normal subjects duodenal acidification, bile acid and an unknown factor contained in the meat soup may participate, at least in part, in postprandial motilin release.
The inhibitory effect of oral glucose load and insulin-induced hypoglycemia on motilin release may be attributable to a certain mediator mechanism which remains to be studied.