Effect of parenteral zinc on paraquat toxicity in the rat

The purpose of this study was to determine if elevating lung zinc would prevent the lethal effect of paraquat. Several doses of zinc sulfate (20, 40, and 80 mg/kg) were administered intraperitoneally for 7 days and lung ainc measured. Only 80 mg/kg produced a significantly increase. Acute administration of 80 mg/kg zinc sulfate produced an 81% elevation in lung zinc within 4 hr. Animals were treated with zinc sulfate (80 mg/kg) followed 4 hr later by paraquat (42.5 mg/kg). They also received 2 additional doses of zinc during the next 48 hr. Zinc treated animals were not protected against the lethal effect of paraquat but, instead, had a higher fatality rate than animals treated with paraquat alone.