COMPARISON OF LEVELS OF CYTOCHROMES-P-450, CYP1A2, CYP2E1, AND THEIR RELATED MONOOXYGENASE ACTIVITIES IN HUMAN SURGICAL LIVER SAMPLES

Hepatic microsomal cytochromes P-450 CYP1A2, and CYP2E1 contents and c atalytic activities have been simultaneously investigated in 42 patien ts undergoing diagnostic liver biopsy. CYP1A2 contents, measured by We stern blotting, were correlated with methoxyresorufin-O-demethylation and ethoxyresorufin-O-deethylation (r = 0.65 and r = 0.66, p < 0.001, respectively). CYP2E1 contents were correlated with 1-butanol oxidatio n and 6-hydroxylation of chlorzoxazone (r = 0.75 for both, p < 0.001). CYP1A2 catalytic activities varied by 30- to 40-fold, whereas CYP2E1 activities varied by 6- to 20-fold. In our study, these variations wer e not related to liver diseases or cancer of the digestive tract nor t o alcohol drinking or smoking habits, because patients were alcohol- a nd tobacco-free for 1 month before the study. Other environmental fact ors, diet habits, and/or genetic factors could explain the large inter individual variations observed.