Glucagon

Glucagon is a polypeptide of 29 amino acids produced by the pancreatic alpha cells. In addition to its well known effect of elevating blood glucose concentration, glucagon functions to inhibit gastric and pancreatic secretions. It stimulates fluid secretions from the intestine and suppresses the release of gastrin. Tumors producing large amounts of glucagon are referred to as glucagonomas. Glucagonproducing A cells occupy dispersed locations throughout the islet with some clustering along the periphery. They constitute 15% to 20% of the islet cell population. This antibody stains the cytoplasm in A cells of the endocrine pancreas and reacts with glucagon in a number of mammalian species.