Immunofluorescent localization of enteroglucagon cells in the gastrointestinal tract of the dog

Abstract

Localization of the endocrine polypeptide cells responsible for ;glucagon-like immunoreactivity' in the gastrointestinal tract of the dog has been achieved with an immunofluorescent technique using antibodies raised against porcine pancreatic glucagon. The cells, for which we prefer the term ;enteroglucagon', could only be demonstrated by this technique in tissues fixed in carbodiimide. The enteroglucagon cells possess cytological, cytochemical, and ultrastructural characteristics in common with those of the pancreatic alpha(2) cell and they are equivalent in the stomach to the A cell and in the intestine to the L cell of the Wiesbaden terminology. Their distribution, predominantly in fundus and jejunum, correlates precisely with the distribution of glucagon-like immunoreactivity by radioimmunoassay and bioassay. The storage form of enteroglucagon differs in many respects from that of pancreatic glucagon although there are some close resemblances between the two forms of specific hormone-containing granule. Elucidation of the role of enteroglucagon should be assisted by the ability to demonstrate enteroglucagon cells.