GALACTOSE METABOLISM IN THE NEWBORN INFANT

Abstract

A marked increase was noted in the production of labeled carbon dioxide from galactose-1-C14, and a lesser increase from glucose-1-C14, by erythrocytes of newborn infants as compared to those of adults. It is considered that the increased metabolic activity reflects a greater capability of erythrocytes of newborns to phosphorylate the particular sugars. Estimates were made of galactose-1-phosphate uridyl transferase and galactokinase activities of intact erythrocytes by incubation with galactose-1-C14. Intracellular transferase activity, as measured by the ratio of labeled galactose-1-phosphate to labeled uridine diphosphate galactose, correlated with hemolysate measurements, but the amount of labeled nucleotide alone did not. Intracellular galactokinase activity correlated with hemolysate values provided that galactokinase activity was considered to be represented by the sum of the galactose-1-phosphate and nucleotide produced during incubation with galactose. The rate of removal of galactose from the blood of newborns after intravenous administration was slower than with adults. However, the rate of disappearance cannot be considered to reflect galactose utilization until more is known concerning regulatory factors in the newborn infant.