The relation between inhibition of glycolysis and stimulation of oxygen uptake due to glucagon in livers from rats in different metabolic conditions

The relation between the effects of glucagon on oxygen consumption and glycolysis in livers from rats under different metabolic conditions was examined. Respiration of substrate-free perfused livers with different glycolytic fluxes, induced by changes in the pattern of food intake, responds differently to the infusion of 1 nM glucagon. The increases in oxygen uptake caused by 1 nM glucagon correlate reasonably well with the absolute decreases in glycolysis. The degree of inhibition of glycolysis is approximately constant (58 per cent) for all metabolic conditions. When no recovery of glycolysis occurs upon cessation of glucagon infusion, the same happens with oxygen consumption, which remains stimulated. It is concluded that in livers with no appreciable biosynthetic activities, the action of glucagon on respiration and glycolysis may be interpreted in terms of an interaction of interpreted in terms of an interaction of cytosolic and mitochondrial ATP generating processes.