What is "xenin"

Xenin is a peptide hormone produced by a subpopulation of chromogranin A-positive endocrine cells in the mucous membrane of the duodenum. The peptide has been found in humans, dogs, pigs, rats, and rabbits.

In humans, xenin circulates in the blood plasma. There is a relationship between peaks of xenin concentration in the plasma and the third phase of the Migrating Motor Complex. For example, infusion of synthetic xenin in fasting volunteers will cause phase III activity. After a meal (the ' postprandial state'), infusion of xenin increases both frequency and the percentage of aborally propagated contractions. In higher concentrations xenin stimulates exocrine pancreatic secretion and inhibits the gastrin-stimulated secretion of acid in dogs. Xenin is also produced in neuroendocrine tumors of the duodenal mucosa.

In vitro, xenin interacts with the neurotensin receptor 1.