CONTRIBUTION OF GASTRIN TO CYSTEAMINE-INDUCED GASTRIC-ACID SECRETION IN RATS

The role of circulating gastrin in cysteamine induced gastric acid secretion was examined in conscious male Wistar rats, provided with a portal vein catheter, a jugular vein catheter and a pyloric drainage tube. Intravenous infusion of 0.3 nmol/kg.30 min of gastrin 17-I resulted in serum gastrin concentrations of 1138+/-151 pg/ml and gastric acid secretion of 104+/-36 mumol H+/kg.30 min. This acid response was abolished by intravenous injection of 60 mul of a gastrin-antiserum, indicating the efficacy of immunoneutralization with this antiserum in vivo. Intravenous bolus administration of 125 mg/kg of cysteamine induced increases in serum gastrin concentration (864+/-96 pg/ml) and gastric acid outputs (107+/-27 mumol H+/kg.30 min) not significantly different from the gastrin 17-1 infusion experiments. Gastrin antiserum abolished cysteamine-induced gastric acid secretion, indicating that gastric acid secretion induced by 125 mg/kg of cysteamine is largely mediated by circulating gastrin in rats.