Role of the small intestine and gastric antrum in pancreatic polypeptide release.

Gastrointestinal peptides have been proposed to play an important role in the pancreatic polypeptide response to a meal. These studies examine the role of the small intestine and gastric antrum in pancreatic polypeptide release in unanesthetized dogs. Intestinal perfusion with 5% liver extract in seven dogs resulted in a significant increase (P less than 0.05) in serum pancreatic polypeptide concentration (mean delta PP = 35.0 +/- 10.5 pM). Antrectomy without truncal vagotomy in four of these dogs significantly inhibited (P less than 0.05) this response. In five other dogs, antrectomy inhibited the pancreatic polypeptide response to an ingested meat meal by 81.9 +/- 4.5% (P less than 0.01). To further delineate the mechanism by which antrectomy inhibits pancreatic polypeptide release, the pancreatic polypeptide response to a meal was measured in four dogs before and after selective antral denervation. Antral denervation inhibited pancreatic polypeptide release to a degree similar (81.5 +/- 13.4%) to that previously observed after antrectomy. These studies have demonstrated an intestinal phase of pancreatic polypeptide release. They also suggest that antrectomy exerts its inhibitory effect on pancreatic polypeptide release by partially denervating the pancreas.