Secretin-Gastric Emptying and Motor Activity: Natural Versus Synthetic Secretin

Abstract

Summary

Studies were made in four dogs with gastric fistulas to compare the effects on gastric emptying of natural and synthetic secretin. In some experiments gastric electrical and motor activity using electrodes and strain gauges was studied simultaneously with emptying. In three other dogs with gastric fistulas the acid inhibitory effects of the two secretins were tested against a continuous intravenous infusion of 4 μg/kg hr of penta-gastrin.

Natural and synthetic secretin in doses greater than 1 U/kg hr (4 and 8 U/kg hr) delayed significantly the gastric emptying of 0.15 M saline meals and natural secretin was more potent than synthetic secretin. Associated with the delay in gastric emptying was a decrease in the force and frequency of antral contractions. Antral and duodenal slow waves were unchanged. Natural and synthetic secretin were equipotent as inhibitors of penta-gastrin-stimulated acid secretion and the doses were less than those required for delay of gastric emptying.

These studies suggest that (a) inhibition of gastric emptying by secretin requires much larger doses of secretin than those for inhibition of gastric acid secretion, (b) natural secretin was more potent that synthetic secretin for gastric emptying and that (c) delay in gastric emptying was associated with decreased force and frequency of antral contractions.