MPTP potentiates iron-induced lipid peroxidation without the involvement of free radicals derived from oxygen.

We demonstrate here that MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) potentiates iron-catalyzed lipid peroxidation in intact erythrocytes, whereas it does not mediate hydrogen peroxide catalysed lipid peroxidation. The malonaldehyde formation which results from this lipid peroxidation is generated in the absence of superoxides, hydroxyl radicals, hydrogen peroxide or singlet oxygen. The MPTP reaction is blocked by addition of iron +2 chelator but not by iron +3 chelator. These results suggest that an iron-MPTP complex promotes the formation of lipid peroxidation by interacting directly with membrane polyunsaturated lipids.