Nicardipine and Nifedipine Inhibit Fatty Acid Desaturases in Rat Liver Microsomes

Abstract

Nicardipine and nifedipine, Ca channel blockers, inhibited rat liver microsomal desaturases, though verapamil, methoxyverapamil, cinnarizine, flunarizine, and diltiazem did not, However, nicardipine and nifedipine apparently did not inhibit the fungal desaturation in Mortierella alpina 1S-4. Nicardipine inhibited rat liver microsomal Delta 5 desaturase specifically (50% inhibitory concentration, 170 mu M), and nifedipine inhibited Delta 6 desaturase specifically (78 mu M). The inhibition of nicardipine and nifedipine is uncompetitive,the K-i values for Delta 5 and Delta 6 desaturases being 62 and 44 mu M, respectively.