Abstract
Since insulin-induced hypoglycemia or a rapid fall of blood glucose (cataglycemia) stimulates the secretion of pancreatic glucagon in dogs, changes in plasma glucagon were investigated in normal subjects following intravenous administration of insulin (0.1 U/kg of body weight) or discontinuance of glucose infusion. A significant rise in plasma glucagon was observed in hypoglycemia induced by insulin injection, whereas cataglycemia did not induce any rise in plasma glucagon in man.
To observe the effect of sugar on the secretion of pancreatic glucagon, 5 % solution of each sugar was infused into the femoral vein of mongrel dogs, and insulin and glucagon in the pancreaticoduodenal vein were measured. The level of pancreatic glucagon was decreased after glucose or xylitol infusion. No change in glucagon level was observed upon infusion of fructose, mannose or ribose. Insulin level in the pancreaticoduodenal vein increased following infusion of glucose, ribose or xylitol. Fructose or mannose did not produce any changes in plasma insulin or glucagon in the pancreatic vein. These results do not support the intra-insular action of insulin and glucagon.
