On the effect of xenin and xenin fragments on exocrine pancreas secretion in vivo

A stimulatory effect on exocrine pancreas secretion could be demonstrated w ith high concentrations of the 25-amino-acid peptide xenin in non-anestheti zed dogs. This peptide has been isolated from gastric mucosa and it is part of a structural coat protein. It has close structural similarities to neur otensin. The longer C-terminal fragments xenin-(13-25) and xenin-(18-25) ar e essential for the stimulation of exocrine pancreas secretion in vivo. The smaller peptide fragments xenin-(21-25) and xenin-(22-25) failed to stimul ate the pancreas as well as the N-terminal peptide fragment xenin-(1-23). T he stimulatory effects of xenin may be mediated via neural neurotensin path ways, because neurotensin receptor blockade abolished the stimulatory effec t on pancreatic secretion. Cholinergic pathways are not involved, because a tropine had no inhibiting effect. (C) 1999 Elsevier Science B.V. All rights reserved.