Glucagon Deficiency Induced by Extirpation of Alpha Islets of the Fowl Pancreas

Abstract

The endocrine-morphologic relationship between the pancreatic islet cells of the fowl was investigated by morphologic observation of the architecture and distribution of the islets and physiologic examination of fowls deprived of the alpha-islet-containing portion of the pancreas. There were 2 types of islets in the fowl pancreas: one was an “alpha” islet composed of alpha and delta cells and the other -was a “beta” islet made of beta and delta cells. Beta islets were scattered throughout the gland, while alpha islets were confined to the 3rd and splenic lobes. It was suggested that carbohydrate metabolism was essentially the same in the fowl as in the mammal, because they exhibited the same sensitive hyperglycemic response to glucagon and hypoglycemic response to insulin. A physiologic investigation of changes in fowls deprived of alpha islets was accomplished by means of selective removal of the alpha-islet-containing portion, or the 3rd and splenic lobes, from the pancreas. The birds having received such partial pancreatectomy developed severe hypoglycemia, which brought about convulsion and eventual death within 12 to 36 hours after operation. Death always occurred 10 to 30 min after paralysis of the hind legs and radical convulsion had been manifested. The blood sugar level usually averaged 50 mg /100 ml. when convulsions began. The severe hypoglycemia following the operation disappeared completely after the administration of glucagon and reappeared when the effective period of glucagon expired. This situation was induced repeatedly, even several times, after glucagon administration. No deaths occurred as long as glucagon therapy was continued. It is obvious that hypoglycemia observed in fowls deprived of alpha cells is due to deficiency of glucagon and maintenance of insulin secretion. This fact shows that glucagon is an indispensable hormone for carbohydrate regulation and the maintenance of life and that it originates from the alpha cells of the pancreatic islet.