NADH and NADPH inhibit lipid peroxidation promoted by hydroperoxides in rat liver microsomes.

Lipid peroxidation induced through cytochrome P-450 activation of cumene hydroperoxide, linolenic acid hydroperoxide and peroxidized phosphatidylcholine in rat liver microsomes is markedly inhibited by either NADH or NADPH. This inhibition is not due to an antioxidant effect. Conversely, cumene hydroperoxide decomposition is stimulated by the reduced pyridine nucleotides but not by some modifiers of cytochrome P-450 (SKF-525A, metyrapon and aniline). The mechanism by which NADH and NADPH prevent lipid peroxidation may involve a reduction of the hydroperoxides mediated by cytochrome P-450 and occurring without formation of free radical forms that are usual sparkers of lipid peroxidation.