[Effect of endogenous lipid peroxides on respiration in rat liver mitochondria]

Effect of Fe2+- and ascorbate-induced lipid peroxidation on mitochondrial respiration in 3 and 4 states (according to Chance) is studied. Peroxidation was shown to result in an increase of the oxygen uptake rate in 4th state, and in the KCl-containing medium (but not in sucrose medium) it caused a decrease of the oxygen uptake rate in the phosphorylating state, which partially reversed when cytochrom c was added. These effects were observed only after the development of peroxidation (after "slow" flash of chemiluminescence), and the value of and effect correlated with the content of peroxidation products unsaturated fatty acids. No considerable differences in the damaging effect of peroxidation were observed under incubation of mitochondria in KCl, NaCl and choline containing media.