Failure of Blood Glucose Levels to Reflect Hepatic Glycogenolysis; Experiences with Glucagon.

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Abstract
Glucagon was administered subcutaneously, intraperitoneally, and intravenously to normal and adrenodemedullated rats, in doses ranging from 5 to 80 [mu]g/100 g. Distinct rises in blood glucose were regularly observed after intravenous, and usually, after intraperitoneal, administration to normal animals. Subcutaneous administration often failed to produce a rise in blood glucose in normal animals, and regularly failed to do so in the demedul-lated rats. However, the glycogen depletion induced by subcutaneous glucagon was at least as great as that following intravenous or intraperitoneal injection, in all experiments. Declines in liver glycogen one hour after injection ranged from 70% to 95% (from control levels of 2% to 3.5%). Since small increases in the rates of glucose disposal mechanisms can completely mask the anticipated hyperglycemic effect of liver glycogen mobilization, the blood glucose curve cannot be used as a measure of hepatic glycogenolysis.