Response of extrapancreatic glucagon to glycemic changes under chronic insulin deficiency in dogs

Since the secretion of pancreatic glucagon is largely influenced by the changes in the blood glucose level, the response of extrapancreatic glucagon was investigated in totally pancreatectomized dogs under chronic insulin deficiency. Insulin-induced hypoglycemia did not alter plasma glucagon in the portal vein in a group of 5 pancreatectomized dogs, but the decrease of the blood glucose was small, by 70 mg/100 ml, in spite of a large amount of insulin. The administration of 2-deoxyglucose did not cause any changes in plasma glucagon in the portal vein in a group of 6 pancreatectomized dogs. Glucose-induced hyperglycemia, both transient and continuous, did not cause any changes in plasma glucagon in the portal vein, although blood glucose was significantly elevated. It is concluded that regulation of extrapancreatic glucagon differs from that of pancreatic glucagon.