Effect of secretin on gastric function in normal subjects and in patients with duodenal ulcer

The effect of constant intravenous infusion of secretin in doses of 0.25, 0.50, 1.50, and 3.0 mug per kg per hr on meal-stimulated acid secretion was measured in vitro titration to pH 5.0. The pattern and degree of secretin inhibition of food-stimulated acid secretion depended on when the secretin infusion was begun, the effect being more pronounced when the secretin was begun 1 hr before the test meal than when the meal and secretin infusions were begun simultaneously. Inhibition of acid secretion in normals was approximately the same as in 2 patients with pancreatic exocrine insufficiency who could secrete only small amounts of pancreatic bicarbonate in response to secretin. Secretin in dose of 0.25 and 0.5 mug per kg per hr inhibited acid secretion only slightly, whereas 3.0 mug per kg per hr completely stopped acid secretion. Inhibition of acid secretion by secretin was similar in controls and in patients with duodenal ulcer. Secretin also reduced the rise in serum gastrin concentration after the meal, and delayed gastric emptying; both responses were approximately the same in normals and in duodenal ulcer patients. Secretin inhibited basal gastric acid secretion but had no consistent effect on basal serum gastrin concentration.