Effect of glucagon on metabolism of glucose and acetate by isolated rat liver

¹ Department of Biochemistry, University of Melbourne, Melbourne, Australia

A simple method of perfusing the isolated rat liver with a small quantity of fluid is described. The technique was used to study the effect of purified glucagon on the oxidation of radioactive glucose and acetate by the liver. The changes produced by the hormone in the labeling of the C¹⁴O₂ recovered from the tissue show that it promoted an increase in the utilization of unlabeled endogenous substrate by the preparation. A study of the labeling of the -keto-glutaric and pyruvic acids contained in the perfusates has indicated that glucagon promotes an increased entry of unlabeled material into the metabolic pathway at a point after pyruvic acid and at or before -ketoglutaric acid. It is suggested that the dilution of the radioactive C¹⁴O₂ expired by the preparation was due at least in part to an increased breakdown of fats by the liver.