Determination of the mean cell age of erythrocytes from diabetic subjects with pyruvate kinase.

The pyruvate kinase activity of erythrocytes from normal and diabetic subjects was examined in order to establish this enzyme as a valid indicator of mean cell age in the studies of age-dependent erythrocyte functions. This study reveals that the enzyme activity in the erythrocytes was not affected by the condition of diabetes and suggests that it may provide a simple means for the determination of cell age in erythrocyte insulin binding studies. Present data further indicate that the mean cell age of the erythrocytes from diabetic patients was not significantly different from normal although insulin binding to erythrocytes was markedly reduced when compared with that in the normal subjects.