Raucy J L, Schultz E D, Wester M R, Arora S, Johnston D E, Omdahl J L, Carpenter S P
The Agouron Institute, Division of Gastroenterology, La Jolla, CA 92037-4696, USA.
Drug Metab Dispos. 1997 Dec;25(12):1429-35.
Cytochrome P450 (CYP) 2E1 is implicated in a variety of chemically initiated hepatotoxicities, including alcoholic liver disease. These pathological conditions arise from increased production of reactive intermediates caused by elevated enzyme concentrations. Thus, the ability to detect enhanced CYP2E1 levels would aid in identifying individuals at high risk for xenobiotic-promoted liver injury. With this in mind, the present investigation assessed in vivo chlorzoxazone metabolism and compared pharmacokinetic parameters with CYP2E1 expression in blood. Twenty-two subjects were recruited and divided into two groups, control subjects and alcohol abusers, based on responses to two screening questionnaires. Those individuals with higher survey scores, i.e. those who consumed alcohol more frequently, exhibited higher rates of chlorzoxazone metabolism. Indeed, a correlation (r = 0.66, p < 0.01) was obtained when scores were compared with the pharmacokinetic parameter AUC for chlorzoxazone. Lymphocyte microsomes isolated from blood samples obtained from these same individuals were subjected to immunoblot analyses to detect CYP2E1 levels. That lymphocytes contained CYP2E1 was confirmed by reverse transcription-polymerase chain reaction and sequence analysis of the cDNA. Quantification of immunoreactive bands revealed that levels of this P450 were 2.3-fold higher in alcoholics than in control subjects. This increase in lymphocyte CYP2E1 content in alcoholic subjects coincided with a 2.1-fold increase in chlorzoxazone clearance and a 2-fold decrease in the AUC for chlorzoxazone. Importantly, a correlation (r = 0.62, p < 0.01) was observed between CYP2E1 content in lymphocytes and chlorzoxazone clearance rates. Thus, monitoring lymphocyte CYP2E1 expression may provide a substitute for estimating hepatic activity of this P450.
细胞色素P450（CYP）2E1与多种化学物质引发的肝毒性有关，包括酒精性肝病。这些病理状况源于酶浓度升高导致的反应性中间体生成增加。因此，检测CYP2E1水平升高的能力将有助于识别易受外源化合物促进的肝损伤影响的高危个体。考虑到这一点，本研究评估了氯唑沙宗的体内代谢，并将药代动力学参数与血液中CYP2E1的表达进行了比较。根据两份筛查问卷的回答，招募了22名受试者并将其分为两组，即对照组和酗酒者。那些调查得分较高的个体，即饮酒更频繁的个体，氯唑沙宗代谢率更高。事实上，将得分与氯唑沙宗的药代动力学参数AUC进行比较时，得到了相关性（r = 0.66，p < 0.01）。从这些个体采集的血液样本中分离出淋巴细胞微粒体，进行免疫印迹分析以检测CYP2E1水平。通过逆转录-聚合酶链反应和cDNA序列分析证实淋巴细胞含有CYP2E1。免疫反应条带的定量分析表明，酗酒者中这种P450的水平比对照组高2.3倍。酗酒受试者淋巴细胞CYP2E1含量的增加与氯唑沙宗清除率增加2.1倍以及氯唑沙宗AUC降低2倍相吻合。重要的是，观察到淋巴细胞中CYP2E1含量与氯唑沙宗清除率之间存在相关性（r = 0.62，p < 0.01）。因此，监测淋巴细胞CYP2E1表达可能为估计该P450的肝脏活性提供一种替代方法。
