Role of estradiol in chromium-induced oxidative stress.

This study investigated the role of 17beta-estradiol in chromium-generated oxidative stress in order to determine whether it has a detoxifying activity or increases the toxic effects of chromium compounds. Reduced glutathione (GSH) levels, membrane lipid peroxidation (levels of malondialdehyde -- MDA), glutathione peroxidase (GPx), and superoxide dismutase (SOD) activities were measured in blood. Isolated mitochondria were used to investigate the MDA levels and hydroxyl radical (OHradical) generation. The results showed a varying influence of estradiol on the chromium-induced oxidative stress. This paper demonstrated, that 17beta-estradiol showed a positive effect when erythrocytes were exposed to moderate concentrations of CrVI and increased the levels of erythrocytal GSH. Estradiol did not show any interactions with chromium on the antioxidative enzymes (SOD in erythrocytes and GPx in whole blood) activity measurements. Additionally, estradiol played a generally positive role in the chromium-induced lipid peroxidation in erythrocytes. Unexpectedly, the interaction of estradiol with chromium was found in human mitochondria, where estradiol increased the MDA levels induced by both forms of chromium. Estradiol also increased the OHradical generation triggered with CrVI. It appeared that estradiol acted protectively on lipid peroxidation caused by chromium in erythrocytes but gave an interaction with Cr in mitochondria, which partially correlated with hydroxyl radical formation in this organelle.