A role for pancreatic polypeptide in the regulation of gastric emptying and short-term metabolic control

Context: Previous studies using pancreatic polypeptide (PP) infusions in humans have failed to show an effect on gastric emptying, glucose metabolism, and insulin secretion. This might be due to the use of nonhuman sequences of the peptide. Objective: The objective of this study was to use synthetic human PP to study gastric emptying rates of a solid meal and postprandial hormone secretion and glucose disposal as well as the gastric emptying rate of water. Design: This was a single-blind study. Setting: The study was performed at a university hospital. Participants: Fourteen healthy adult subjects were studied. Interventions: Infusion of saline or PP at 0.75 or 2.25 pmol/kg(.)min was given to eight subjects (gastric emptying of solid food), and infusion of saline or PP at 2.25 pmol/kg(.)min was given to six subjects (gastric emptying of water). Main Outcome Measures: The main outcome measures were gastric emptying of solids (scintigraphy), hunger ratings (visual analog scale), and plasma concentrations of PP, insulin, glucagon, somatostatin, glucagon-like peptide 1, glucose, and gastric emptying of plain water (scintigraphy). Results: PP prolonged the lag phase and the half-time of emptying of the solid meal. The change in hunger rating, satiety, desire to eat after the meal, or prospective consumption was not affected. The postprandial rise in plasma glucose was prolonged by PP. The postprandial rise in insulin was also delayed by PP. PP had no significant effect on the emptying of water. Conclusions: PP inhibits gastric emptying of solid food and delays the postprandial rise in plasma glucose and insulin. PP is suggested to have a physiological role in the pancreatic postprandial counter-regulation of gastric emptying and insulin secretion.