The effect of light on the toxicity of paraquat in the mouse.

The role of light is known to be important in the herbicidal action of paraquat, the active ingredient of Gramoxon. Experiments were therefore performed to establish whether illumination influences paraquat toxicity in some way in mice. Besides the 72-hr survival rate, studies were made of the body weight/lung weight ratio, the antioxidant enzyme activity and the lipid peroxidation in mice treated with the LD50 of paraquat and kept in the dark or under illumination. All of the measured parameters indicate that illumination enhances the toxic properties of paraquat in mice.