Suppression of postprandial lower esophageal sphincter pressure and pancreatic polypeptide by duodenal exclusion.

It has previously been shown that peptone perfusion of an excluded duodenum results in increased lower esophageal sphincter pressure (LESP). The current study was undertaken to determine the effect of duodenal exclusion on the increase in lower esophageal sphincter pressure normally observed postprandially. Six dogs had measurement of fasting and postprandial LESP with simultaneous measurement of gastrin, vasoactive intestinal peptide (VIP), and pancreatic polypeptide (HPP). The animals then underwent duodenal exclusion via a Roux-Y pylorojejunostomy. Experiments were repeated after recovery. All dogs demonstrated the expected marked rise in LESP during control meals (P less than 0.001). Duodenal exclusion completely abolished the increase in LESP normally observed postprandially. This difference in response was significant at the level of P less than 0.005. The response of gastrin and VIP to feeding were not altered in any way by duodenal exclusion. Pancreatic polypeptide release, however, was markedly attenuated by duodenal exclusion. This difference from the control period was significant at the level of P less than 0.05. Duodenal exclusion abolished the response of the LES to feeding and is accompanied by a concomitant decrease in release of pancreatic polypeptide, a hormone with known stimulatory effects on the LES. It appears that the duodenum may make a significant contribution to postprandial increases in LESP.