PANCREATIC PEPTIDE YY IN ALLOXAN-DIABETIC MICE

Peptide YY (PYY) immunoreactive material was detected in the splenic a nd duodenal portions of the adult mouse pancreas, using immunocytochem ical and immunochemical methods. Cells displaying PYY immunoreactivity generally occurred at the islet periphery. Double immunostaining enab led localization of PYY to a major subpopulation of the glucagon cells and to subpopulations of the pancreatic polypeptide (PP) cells and th e somatostatin cells. In contrast, no PYY immunoreactivity occurred in the insulin cells. In alloxan-treated hyperglycemic mice, PYY immunor eactive cells were increased in number and distributed throughout the islets, in parallel with the glucagon, PP, and somatostatin cells. Ana lysis by radioimmunoassay indicated a significant increase in the conc entration of pancreatic PYY after alloxan treatment in the splenic por tion of the pancreas, but not in the duodenal portion. Pancreatic gluc agon concentrations were not significantly changed. It is concluded th at the islet content of PYY increases in alloxan diabetes, which might contribute to the accompanying alterations in islet function.