Pancreatic polypeptide and glucagon : non-random distribution in pancreatic islets.

Abstract When the technique of immunofluorescence is applied to rat pancreas to detect insulin, glucagon, somatostatin and pancreatic polypeptide (PP), two populations of islets having distinct cellular content and topographical distribution can be recognized. Islets from the lower part of the head show a well-defined rim of PP-containing cells, but very few or no glucagon-containing cells. Islets from the body and tail display the familiar rim of glucagon-containing cells and possess very few or no PP-containing cells. This inverse relationship between glucagon and PP-cells in different parts of the pancreas means that caution must be exercised when interpreting functional or morphological observations using different pancreatic fractions.