Pancreatic polypeptide (PP)- and glucagon cells in the pancreatic islet of Xiphophorus helleri H. (Telecostei). Correlative immunohistochemistry and electron microscopy.

Correlative immunohistochemical and electron microscopical studies on the pancreatic islet of the telecost fish Xiphorphorus helleri using antibodies to pancreatic polypeptide (PP) and glucagon show that separate cell types are responsible for the production of these peptides. The PP-cells correspond to the previously described "A2-cells with round granules", while the "A2-cells with crystalline granules" are the true glucagon cells. An earlier suggestion that there are two types of glucagon cells in teleost islets is therefore withdrawn.