Role of the distal pancreas in pancreatic polypeptide release

In two previous studies, postprandial pancreatic polypeptide (PP) release was inhibited when pancreatic denervation was combined with distal pancreatectomy. In contrast, postprandial PP release was unaffected by pancreatic denervation without a distal pancreatectomy. These findings suggested a role for the distal pancreas in regulation of postprandial PP release. To examine this possibility, we performed distal pancreatectomy on four mongrel dogs. Pancreatic polypeptide response to i.v. insulin (0.5 U/kg), a meal, and an infusion of cholecystokinin octapeptide (CCK-8; 50 ng/kg/h) were measured in conscious dogs before and after distal pancreatectomy. Insulin-induced hypoglycemia stimulated PP release both preoperatively (47.0 +/- 8.8 ng.[0-120]min/ml) and postoperatively (61.6 +/- 9.2 ng.[0-120]min/ml). Ingestion of a meal also evoked significant PP release preoperatively (85.8 +/- 22.1 ng.[0-180]min/ml) and postoperatively (105.8 +/- 42.2 ng.[0-180]min/ml). CCK-8 elicited only a small increase in circulating PP, which was not influenced by distal pancreatectomy. These findings demonstrate that distal pancreatectomy does not alter PP response to insulin, a meal, or CCK-8.