Changes in circulating levels of cholecystokinin,gastrin, and pancreatic polypeptide after small bowel resection in dogs

The postresectional meal-stimulated concentrations of gastrin were significantly increased 6 weeks after intestinal resection, and returned to preoperative levels within 10 weeks. Preoperatively, the onset of release of cholecystokinin occurred 120 minutes after food intake, 3 weeks after surgery it occurred at 90 minutes after food intake, and at 10 and 15 weeks after operation at 15 and 5 minutes after food intake, respectively. Postprandial release of pancreatic polypeptide was not affected by massive small bowel resection. We suggest that postresectional hypergastrinemia results from loss of a distal inhibitor and that the abnormally high basal concentrations of gastrin may augment the basal pancreatic polypeptide. We further suggest that the increased cholecystokinin concentrations, and the alterations of the temporal pattern of the release, are secondary to accelerated gastric emptying and intestinal transit. The mechanism responsible for postresectional hypergastrinemia is short-lived but the mechanism for postresectional increases in cholecystokinin release is not.