GLUCAGON HYDROCHLORIDE is a polypeptide secreted by the alpha cells of the pancreas. When injected into most individuals it causes a rapid increase in blood glucose. Thus it has the opposite effect of insulin which is produced by the beta cells. Although both glucagon HCl and insulin have a profound influence upon carbohydrate metabolism, these two pancreatic secretions exert their action at different sites. Insulin alters cell permeability to glucose, stimulates conversion of glucose to glucose-1-phosphate, and also influences the citric acid cycle. Glucagon HCl acts primarily in the liver where it stimulates phosphorylase activity which in turn increases formation of glucose-1-phosphate from stored glycogen.
Shortly after the discovery of insulin in 1922, Collip1 called attention to an initial hyperglycemic response that followed injection of pancreatic extracts into animals. Kimball and Murlin2 pursued this phenomenon further and suggested that it might not be caused by insulin but by