Interaction between dual NADPH-dependent reactions of paraquat in mouse brain microsomes.

Paraquat stimulated NADPH-dependent lipid peroxidation in mouse brain microsomes, while it suppressed lipid peroxidation induced by NADPH plus ascorbate. The stimulation of lipid peroxidation by paraquat was inhibited by N-ethylmaleimide (NEM). However, NEM attenuated the inhibitory effect of paraquat on lipid peroxidation elicited by NADPH in combination with ascorbate. These results suggest that an NADPH-dependent reaction which is susceptible to NEM might share an electron from NADPH with the alternative reaction, lipid peroxidation, in the presence of paraquat in mouse brain microsomes.