Phenotype distribution and gender-related differences of CYP2E1 activity in a Chinese population

1. The aim was to investigate the phenotype distribution characteristic and gender-related differences of CYP2E1 activity in a healthy Chinese population. 2. Two hundred and three healthy Chinese subjects (105 men, 98 women) were enrolled in this study. 3. CYP2E1 activity was determined by plasma 6-hydroxychlorzoxazone-to-chlorzoxazone concentration ratio (CHZ-MR) 4h after chlorzoxazone dosing. The concentrations of 6-hydroxychlorzoxazone and chlorzoxazone in plasma were detected by reversed-phase HPLC. 4. The results showed an almost 9-fold variation of CYP2E1 activity at a range of from 0.23 to 1.99. The coefficient of variation CY % was demonstrated with skewness and kurtosis of the ratios in the studied population were 44%, 0.96 and 1.10, respectively. 5. CYP2E1 activity was normally distributed in logarithmic form of 6-OH-CHZ/CHZ as evaluated by Kolmogorov-Smirnov test of normality (p = 0.20). Probit plots of the CYP2E1 activity index of men shifted to the right as compared with that of women. The mean CHZ-MR in men was significantly higher than that in women (0.76 +/- 0.30 versus 0.60 +/- 0.28, p < 0.001), and this difference still existed when normalized by weight (0.73 +/- 0.28 versus 0.66 +/- 0.32, p = 0.016). Body weight correlated positively with CYP2E1 activity in the total group(r < 0.212, p < 0.01).