Effect of glutathione depletion on formation of paramagnetic chromium in Chinese hamster V-79 cells

Abstract

Incubation of Chinese hamster V-79 cells with either buthionine sulfoximine (BSO) or diethylmaleate (DEM) prior to exposure to Na2CrO4 resulted in a depletion of GSH. ESR study shows that the depletion of GSH by BSO caused an increase in the cellular level of Cr(V) intermediate without affecting the level of Cr(III) complex, whereas the levels of Cr(V) and (III) were both suppressed by the depletion of GSH by DEM. GSH depletion by DEM decreased cellular uptake of chromate more than that by BSO. Glutathione reductase activity in cells, which is capable of reducing Cr(VI), was unaffected by BSO, however a strong inhibition was observed in cells treated with DEM, indicating that DEM affects not only GSH levels but also Cr(VI)-reducing enzyme activity. Thus, the depletion of GSH in cells increases Cr(V) formation, based upon the effect of BSO. The role of intracellular GSH in Cr(VI) reduction is discussed.