Release of plasma pancreatic polypeptide in achlorhydric patients after intravenous infusion of gastric inhibitory polypeptide.

In order to evaluate whether gastric inhibitory polypeptide (GIP) could be responsible for the postprandial fall in serum gastrin previously observed in patients with achlorhydria, 7 achlorhydric patients were given 100 ml Lipomul (66 g triglycerides) on one occasion, and 5 of these patients were later given a 30-min intravenous infusion of porcine GIP in a dose of 1 microgram/kg. Following the Lipomul ingestion, serum gastrin fell significantly, whereas no effect on serum gastrin was seen during the intravenous GIP infusion. A small, but significant release of serum insulin was seen shortly after starting the GIP infusion, together with a significant and more sustained release of plasma pancreatic polypeptide (PP). It is concluded that GIP does not lower the serum gastrin levels in achlorhydric patients, but that GIP might participate in the intestinal phase of the PP release.