Glucose-6-phosphate dehydrogenase in vitro correlated with in vivo activity and reticulocytosis.

In vitro activity of erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) does not always correlate with in vivo hemolytic manifestations. Many of these non-correlations are reviewed and can now be explained on the basis of altered substrate affinity and/or altered inhibition by intracellular metabolites. These alterations are not detected by standard assay conditions. The influence of a young erythrocyte population upon in vitro G-6-PD activity was determined and the lower limit of expected values shown to be raised at least to the mean of an average age erythrocyte population.