Inhibition of adriamycin‐promoted microsomal lipid peroxidation by β‐carotene, α‐tocopherol and retinol at high and low oxygen partial pressures

Abstract

Iron‐dependent peroxidation of rat liver microsomes, enhanced by adriamycin, was measured in the presence of increasing concentrations of α‐tocopherol, β‐carotene and retinol at low and high p O 2 . β‐Carotene and α‐tocopherol inhibited lipid peroxidation by more than 60% when present at concentrations greater than 50 nmol/mg microsomal protein at both high and low p O 2 . Retinol inhibited peroxidation by 39% at concentrations greater than 100 nmol/mg microsomal protein. This maximal level of inhibition by retinol was unaltered by p O 2 . However, β‐carotene was more effective than α‐tocopherol or retinol at a p O 2 of 4 mmHg, whereas α‐tocopherol was more effective under aerobic conditions. Since adriamycin‐dependent lipid peroxidation is maximal at low p O 2 , β‐carotene may play a role in protecting against this process.