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, Nonstimula ted LPO was significantly decreased by NF and was not changed by VP an d DT, There was a correlation between the extent of the previously fou nd enzyme-inducing action and the potency of the antioxidant effects o f calcium antagonists. Fe2+/NADPH- and Fe2+/ascorbate-stimulated micro somal LPO was increased by the calcium antagonists studied in the foll owing order: VP>DT>NF (the increase caused by NF was insignificant in Fe2+ NADPH stimulation).