Regional distribution and release of peptide YY with fatty acids of different chain length.

The present study examines peptide YY responses to regional intestinal perfusion of fatty acids of different chain length--dodecanoate and oleate. Six dogs with chronic gastric, duodenal, and jejunal fistulas were studied. Proximal perfusates were administered into the duodenum and diverted through an intestinal fistula placed 45 cm beyond the duodenal cannula. Distal perfusates were administered into the caudal stoma of this intestinal stoma. Peptide YY responses to proximal, distal, and whole-gut perfusion were compared. Proximal perfusion with oleate or dodecanoate failed to release peptide YY. In contrast, distal and whole-gut perfusion with either fatty acid produced significant increases that were of similar magnitude. Immunocytochemical studies demonstrated that peptide YY cells predominated in the canine ileocolonic mucosa and decreased progressively in an orad direction. We conclude that peptide YY release is not dependent on fatty acid chain length and that the duodenum does not play a dominant role in peptide YY release. As such, peptide YY release differs from that of its cousin pancreatic polypeptide and may result at least in part from direct stimulation of the peptide YY cell in the ileocolonic mucosa.