Effect of l-cystine on toxicity of paraquat in mice

Abstract

The protective effect of l-cystine on the toxicity of paraquat (PQ) in mice was studied. Lipid peroxidation in the lung significantly increased after oral administration of PQ (200 mg kg ) and the increase in lipid peroxidation was prevented by l-cystine treatment (300 mg kg ). PQ administration produced an increase in Superoxide dismutase (SOD) activity and a decrease in glutathione peroxidase (GSH-Px) activity in the lung at 24 h after PQ. l-Cystine treatment significantly prevented the changes in SOD and GSH-Px activity in the lung after PQ. l-Cystine treatment prevented the decrease in non-protein sulfhydryl (NP-SH) content in the lung after PQ administration. The tissue distribution and excretion of PQ after PQ administration were not changed by l-cystine treatment. Plasma aspartate aminotransferase activity did not change after PQ administration. These results suggest that l-cystine protects against the toxicity of PQ by maintaining reduced glutathione levels in the cells.