Regulatory peptides in the amphibian pancreas

Abstract

The pancreas from 11 amphibian species was investigated by immunocytochemical methods for the presence of immunoreactivity to a number of antisera raised to mammalian regulatory peptides. The hormones studied were insulin, pancreatic glucagon, enteroglucagon (glicentin), pancreatic polypeptide, somatostatin, gastrin, gastric inhibitory polypeptide, substance P, bombesin, methionine enkephalin, and vasoactive intestinal polypeptide. Immunoreactive cells were detected in all species with the antisera to insulin, somatostatin, pancreatic glucagon, enteroglucagon, and pancreatic polypeptide. The cells stained by the two glucagon antisera and the pancreatic polypeptide antiserum were identical in all species examined. Fine nerve fibres immunoreactive with the antiserum to vasoactive intestinal polypeptide were demonstrable only in the anuran species Hyla arborea (Hylidae). The remainder of the antisera did not detect either endocrine cells or nerve fibres in the species studied.