Xenin is abundantly expressed in gastric, duodenal, and jejunal mucosa, and is found at lower levels in the pancreas. Xenin is released into the circulation postprandially and has been reported to stimulatepancreatic endocrine and exocrine secretion, inhibit gastrin secretion, and influence gastrointestinal motility. Xenin is highly homologous to neurotensin. Xenin and neurotensin are reported to have similar biological effects.