Localization of pancreatic polypeptide (PP)-like immunoreactivity in the pancreatic islets of some teleost fishes

Immunocytochemical staining has revealed that the pancreatic islets of various teleost fishes contain a pancreatic polypeptide (PP)-like substance which cross-reacts with antibodies to mammalian and avian PP. The PP cells were frequently found at the periphery of the islets, as in mammals, and were of irregular shape.