Glycogen Metabolism in the Isolated Liver

¹ From the Division of Medicine, Roswell Park Memorial Institute, Buffalo, and Departments of Radiation Biology and Biochemistry, School of Medicine and Dentistry, University of Rochester, Rochester, New York

Glycogen metabolism was studied in isolated rat liver, using the perfusion apparatus developed by Miller (J. Exper. Med. 94: 431, 1951). It proved possible to maintain stable glycogen levels for as long as 3 hours in this system, at glucose concentrations of 200–300 mg% in the perfusing blood. Glycogen synthesis was observed in isolated livers obtained from fasted animals, at glucose concentrations entirely within the physiological range. At high glucose concentrations, glycogen levels reached 2% or more. Glycogen synthesis was observed both with and without insulin, but it took place at lower glucose concentrations when insulin was added. Infusion of epinephrine induced glycogenolysis in the isolated liver. Norepinephrine was less active as a glycogenolytic agent.