Pancreatic glucagon cells contain endorphin-like immunoreactivity.

Semithin and thin serial sections of rat pancreas were investigated by immunocytochemical techniques using antisera against glucagon and endorphin. The immunocytochemical staining methods revealed that in the rat endocrine pancreas endorphin-like immunoreactivity is contained in glucagon (A-) cells. All secretion granules of glucagon cells that could be identified in adjacent thin sections exhibited glucagon as well as endorphin immunoreactivity. Since glucagon cells are devoid of ACTH-like immunoreactivity it is concluded that the biosynthetic pathway of pancreatic endorphin is not the same as in the pituitary.