THE EFFECTS OF INSULIN AND ADRENALIN ON THE METABOLISM OF GLUCOSE AND LACTATE BY PERFUSED GUINEA PIG HEARTS

Abstract

The effects of insulin and adrenalin on the metabolism of14C-labelled glucose and lactate by perfused guinea pig hearts have been studied. In the absence of other exogenous substrates, adrenalin almost triples the amount of glucose oxidized to CO2, with a concomitant large increase in rates of glycolysis and glycogenolysis. Insulin has little or no effect on the rate of glucose oxidation, but greatly increases lactate accumulation, glycogen synthesis (from glucose), and amino acid labelling from14C-glucose.In hearts from starved animals, or in the presence of acetate, both insulin and adrenalin markedly increase the rate of glucose metabolism. When both insulin and adrenalin are present, both glucose and lactate compete favorably with acetate and endogenous substrates for oxidation.