Antral Content and Secretion of Gastrins in Pigs

Abstract

Whereas component II (gastrin 34-like) constitutes only 5% of the antro-duodenal gastrin, it constitutes approximately half of the gastrins in peripheral blood of most mammalian species. To study whether this discrepancy could be explained by a differential secretion from antrum, gastrin concentrations and component patterns were determined in extracts of antral mucosa in antral venous and peripheral blood of pigs (n = 15). In 6 pigs mucosal biopsies were obtained from the antrum. In 7 pigs the right gastroepiploic vein was prepared so that only antral venous blood was collected. Blood was sampled from the carotid artery in 2 conscious pigs. The total concentration of gastrin in antral mucosa averaged 12.3 ± 0.8 μg per g mucosa (mean ± S.E.M., N: 6). Component III constituted 95%, component II 4%, and components I and IV less than 1%. The total concentration of gastrin in antral venous blood during a basal period was 2.2 ± 0.55 ng per ml (N = 6). During stimulation with meat extract a biphasic increase appeared. Component III constituted 59–65% and component IV 32–33% of the gastrins in antral venous blood. In peripheral blood component II constituted 35–41% and component IV 0–2%. We concluded that the relatively large fraction which component II constitutes of gastrin in peripheral blood cannot be explained by a differential secretion from the antrum. The relatively high concentration of component IV in antral venous blood may be explained by degradation of component III during or immediately after secretion.

Key-words:

• Gastrin, antral
• gastrin, components
• gastrin, release
• pigs
• stimulation, meat extract