Carbon tetrachloride‐induced lipid peroxidation dependent on an ethanol‐inducible form of rabbit liver microsomal cytochrome P‐450

Treatment of rats with ethanol or rabbits with either imidazole or pyrazole, agents known to induce the ethanol-inducible form of liver microsomal cytochrome P-450 (P-450 LMeb), caused, compared to controls, 3-25-fold enhanced rates of CCl4-dependent lipid peroxidation or chloroform production in isolated liver microsomes. No significant differences were seen when the rate of CCl4-dependent lipid peroxidation was expressed relative to the amount of P-450 LMeb in the various types of microsomal preparations. In reconstituted membranous systems, this type of P-450 was a 100-fold more effective catalyst of CCl4 metabolism than either of the cytochromes P-450 LM2 or P-450 LM4. It is proposed that the induction of this isozyme provides the explanation on a molecular level for the synergism seen of ethanol on CCl4-dependent hepatotoxicity.