A survey of endocrine cells in the pancreas of the echidna (Tachyglossus aculeatus) with special reference to pancreatic motilin cells.

Pancreatic endocrine cells were examined in a primitive egg-laying mammal, the echidna, using immunohistochemistry. Immunoreactive endocrine cells were observed using antisera to insulin, glucagon, somatostatin, avian pancreatic polypeptide and bovine pancreatic polypeptide. In addition, motilin-immunoreactive cells were identified in both the endocrine and exocrine pancreas of pouch-young and adult echidnas using three types of motilin antisera. Since the motilin-immunoreactive cells did not cross-react with any other pancreatic hormones tested, they are identified as an independent endocrine cell type.