Stimulation of gastric inhibitory polypeptide in normal and duodenal ulcer patients.

To investigate the role of gastric inhibitory polypeptide (GIP), a potent inhibitor of gastric acid secretion, in the hypersecretion associated with duodenal ulcer, we compared the serum GIP concentrations in 11 healthy subjects and 16 duodenal ulcer patients after the stimulation of GIP release by a mixed meal. Fasting and postprandial serum gastrin and GIP concentrations were measured by radioimmunoassay at frequent intervals after the ingestion of a test meal. The duodenal ulcer patients showed an augmented and significantly greater release of GIP as well as of gastrin compared to normal subjects. These results indicate that a defective GIP release cannot account for the gastric hypersecretion seen in patients with duodenal ulcer. The mechanism of the increased GIP response in patients with duodenal ulcer is not clear from these studies.