Protection against paraquat-induced toxicity with sulfite or thiosulfate in mice.

The toxicity of the herbicide paraquat in mice, measured by the single dose LD50 after 7 days, was significantly decreased by coinjection of thiosulfite (1 g/kg; one time per day for 3 days) or sulfite (0.2 g/kg; one time per day for 3 days). However, the toxicity of paraquat was not changed by coinjection of sulfate (1 g/kg; one time per day for 3 days). The body weight of mice was significantly decreased by paraquat treatment (30 mg/kg, i.p.). However, the decrease of body weight was abolished by coinjection of thiosulfate or sulfite but not by coinjection of sulfate. On the other hand, paraquat significantly decreased reduced glutathione contents in liver. The depletion of the glutathione contents was also abolished by coinjection of thiosulfate or sulfite but not by coinjection of sulfate. These results suggest that the preventive effect against paraquat-induced toxicity with thiosulfate or sulfite may involve the glutathione-dependent detoxication in mice.