Effect of calcitonin on basal and pentagastrin- and calcium-stimulated gastric acid secretion in patients with duodenal ulcer.

Synthetic salmon calcitonin infused intravenously in a pharmacological dose of 2 MRCU/kg/hour resulted in an abrupt and profound inhibition of basal and pentagastrin and calcium induced gastric acid secretion in patients with duodenal ulcer. The inhibition in the sixth 15-minute period of the intravenous infusion of calcitonin amounted to 98.7% (basal acid secretion), 51.8% (pentagastrin-stimulated acid secretion) and 80.9% (calcium-induced acid secretion). There were no significant alterations in the serum calcium and gastrin levels during the intravenous infusion of calcitonin. The slight decrease in serum gastrin concentration in the first 30 minutes of calcitonin infusion cannot explain the strong inhibition of gastric acid secretion produced by calcitonin. It is assumed that calcitonin inhibits directly the parietal cells.