Non-Enzymic Lipid Peroxidation in Microsomes and Microsomal Phospholipids Induced by Anthracyclines

The stimulation of non-enzymic lipid peroxidation by doxorubicin, daunorubicin and 7 derivatives was investigated in extracted microsomal phospholipids and in intact microsomes. Evidence was obtained for the necessity of a free amino-sugar moiety for a stimulative effect on lipid peroxidation. Binding of anthracyclines to RNA (which is present in microsomes) was inhibitory towards stimulation. Drugs that stimulated lipid peroxidation in a non-enzymic system with extracted phospholipids also were stimulative in an enzymic, NADPH-dependent, microsomal system. They were not always effective in intact microsomes without the enzymic system. The role of the enzymic system in the stimulation of anthracycline induced lipid peroxidation is thought to be the reduction of iron ions rather than the stimulation of oxygen radical production via the anthracyclines.