Modulation of pancreatic polypeptide secretion by pancreatico-biliary juice.

Abstract

The only apparent physiological action of pancreatic polypeptide (PP) in man is the inhibition of pancreatic and biliary secretions. The purpose of this study was to test the hypothesis that there exists a feedback loop whereby pancreatico- biliary secretions modulate and/or stimulate PP release into the circulation. We first compared the plasma PP response to an iv infusion of secretin (2 U/kg bolus and 0.125 U/kg infusion over 30 min), with and without simultaneous aspiration and perfusion of the duodenum with normal saline, in 10 healthy subjects. Constant washout of the duodenum with normal saline (10 ml/min) reduced the integrated PP response (IPPR) to iv secretin from 5.7 ± 1.2 to 2.2 ± 0.5 ng-min/ml. In a separate set of experiments in 6 healthy subjects, intraduodenal perfusion of pancreatico-biliary juice did not reduce the plasma PP response to secretin stimulation (IPPR = 5.9 ± 0.9 ng-min/ml). Perfusion of the duodenum with pancreatico-biliary juice alone stimulated the release of PP into the c...