Effect of glucagon on serum insulin, plasma glucose and free fatty acids in man

Abstract

The response of serum immunoreactive insulin (IRI), plasma glucose and free fatty acids to intravenous glucagon was studied in 9 normal subjects and 2 patients with von Gierke's disease. When comparable levels of arterial hyperglycemia were achieved by paired infusions of glucagon and glucose in normal subjects, glucagon administration was associated with significantly higher concentrations of arterial IRI and, in 4 of the 5 subjects, greater A-V glucose differences. The continuous infusion of glucagon for 3.5 hours in 4 normal subjects was associated with an initial rise and a subsequent decline of IRI and glucose values. FFA levels fell progressively throughout the infusions. The acute administration of glucagon near the termination of these infusions produced significant elevations of IRI with little change in blood glucose or FFA concentrations. Similarly, glucagon administration in 2 patients with von Gierke's disease elevated IRI values without raising the blood glucose. These studies suggest that glucagon can directly stimulate insulin release.