Demonstration of hepatic maximum removal capacity (Lm) for galactose in humans

Abstract

Abstract Evidence for the existence of a maximum removal capacity (L m ) for galactose in the human liver has been obtained from the results of galactose titration in each of 12 subjects, who had no liver disease. Intracorporeal removal of galactose was calculated from the known rate of infusion, and from the measured rate of excretion in urine during the period of blood concentration equilibrium, for each of 2 infusions in each subject. At equilibrium, excretion of galactose in urine was proportionate to its peripheral blood concentration. From the data, a titration curve can be constructed which primarily represents hepatic transport of galactose. It is splayed from the theoretical concentration-transfer rate curve. The maximum intracorporeal removal capacity for galactose is normally approximately 500 mg. per minute. Although the greatest part of this removal capacity is hepatic, a small amount of extrahepatic removal probably occurs. Saturation methods appear to be applicable to the study of the liver and to afford another means of assessing hepatocellular function.