Gastroenteropancreatic effects of xenin in the dog

Xenin is a 25 amino acid peptide detected in the gastric mucosa of various mammals. It has since been found in low concentrations in other tissues. Xenin plasma concentrations increase after meals. The present study reports some gastroenteropancreatic effects of this peptide in the dog. Intravenous infusion of 64 pmol/kg min synthetic xenin significantly inhibited pentagastrin-stimulated gastric acid secretion and stimulated exocrine pancreatic secretion of volume and protein. Further, intravenous infusion of xenin in a dose of 1.0 pmol/kg min stimulated jejunal motility in the anaesthetized dog. An intravenous infusion of 32 pmol/kg min xenin raised plasma concentrations of pancreatic polypeptide, vasoactive intestinal polypeptide, insulin and glucagon. The present experiments therefore indicate manifold bioactive properties of intravenously infused xenin in the dog, with jejunal motility the most sensitive target. Conclusions as to the physiological role of xenin cannot be drawn from the present experiments. The release of other hormonal peptides indicates a complex action of xenin.