Studies on Chromated Erythrocytes. Effect of Sodium Chromate on Erythrocyte Glutathione Reductase.

The marked affinity of erythrocytes for hexavalent chromate anion was reported in 1950 by Gray and Sterling (1). Since then, erythrocytes labeled with radioactive sodium chromate have been used extensively for the determination of erythrocyte survival in vivo (1-5) and the determination of blood volume (4-6). The anionic hexavalent form of chromium is bound firmly to erythrocytes, is not reutilized, and is excreted mainly in the urine (2). Gray and Sterling suggested that the hexavalent form of chromium in the erythrocyte is probably bound to hemoglobin. Recent work, however, has shown that not all of the chromium is attached to hemoglobin, but that some of it is combined with a substance of low molecular weight, possibly glutathione (7). Ebaugh, Emerson, and Ross (2) showed that small amounts of chromate, up to 9.5 Fg of chromium per ml of blood, had no apparent effect on the survival of erythrocytes in vivo. When 35 pg per ml of blood was used, however, there was significant hemolysis in vivo during the first 24 hours. Donohue and associates (5) found that amounts below 25 ug of chromium per ml of erythrocytes did not affect erythrocyte survival, but that larger amounts were toxic. In this paper we report the results of studies of the effect of chromate on erythrocyte enzymes. A marked inhibition of glutathione-reductase (GSSG-R) activity was observed. Upon incubation with acetylphenylhydrazine, chromatetreated erythrocytes had an increased tendency to form Heinz bodies, and there was some decrease in glutathione stability.