Effect of multiple administration of calcium antagonists on lipid peroxidation in rat liver microsomes

The effects of three calcium antagonists, nifedipine (NF), verapamil (VP), and diltiazem (DT), on the lipid peroxidation (LPO) in rat liver microsomes were studied. The drugs were administered in oral doses of 50, 40, and 30 mg/kg daily for 21 days in male Wistar rats. Nonstimulated LPO was significantly decreased by NF and was not changed by VP and DT. There was a correlation between the extent of the previously found enzyme-inducing action and the potency of the antioxidant effects of calcium antagonists. Fe2+/NADPH- and Fe2+/ascorbate-stimulated microsomal LPO was increased by the calcium antagonists studied in the following order: VP > DT > NF (the increase caused by NF was insignificant in Fe2+ NADPH stimulation).