Possible mechanism of inhibition by polyamines of lipid peroxidation in rat liver microsomes.

The rate of malondialdehyde formation in rat liver microsomes decreased as concentration of spermine added to the reaction mixture was increased. Inhibitory effect on lipid peroxidation was observed even when spermine was added at 15 min after the onset of reaction. Microsomal lipid peroxidation was markedly increased when extracted lipids were added to the reaction mixture. It was, moreover, found that in the presence of exogeneous microsomal lipids, spermine inhibition was weakened. The character of spermine inhibition with respect to the amounts of exogeneous and endogeneous lipids was shown to be competitive. From these results, it was suggested that spermine interaction with microsomal lipids may be responsible for the inhibition of lipid peroxidation.