Selective inhibition of cytochrome P450 2E1 in vivo and in vitro with trans-1,2-dichloroethylene
Selective inhibition of cytochrome P450 2E1 in vivo and in vitro with trans-1,2-dichloroethylene
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DOI：
10.1021/tx970227g
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发表时间：
1998-07-01
影响因子：
4.1
通讯作者：
Bucher, JR
中科院分区：
文献类型：
--
作者：
Mathews, JM;Etheridge, AS;Bucher, JR
研究了细胞色素P450 (P450) 2E1抑制剂反式-1,2-二氯乙烯（DCE）对肝脏P450的体内外催化活性和总含量的影响。分别在给药前和给药后2、5、12和24 h制备肝微粒体，测定P450总含量和P450 1A2、P450 2A1、P450 2B、P450 2C6、P450 2C11、P450 2D1、P450 2E1和P450 3A的活性。使P450 2E1最大失活的DCE最低剂量为100 mg/kg。P450总含量和P450 1A2、P450 2A1、P450 2B、P450 2C6、P450 2C11、P450 2D1和P450 3A活性在DCE （100 mg/kg ip）处理后24小时内未见显著降低，但P450 2E1活性在DCE处理后2和5小时降低约65%，并在24小时恢复到对照水平。给药5小时后，对肝细胞质酒精脱氢酶、线粒体或微粒体醛脱氢酶活性的影响很小或没有显著影响。DCE对P450的体外失活表现出相同的选择性，>抑制P450 2E1活性80%，不影响其他同工酶。然而，DCE （5 mM）也被证明是P450 1A2和P450 2C6探针活性的良好竞争性抑制剂。P450 2E1的体内抑制伴随着免疫反应蛋白水平的降低，并且在dce处理大鼠的微体的Western blot中出现了约30 kDa的额外免疫反应带，可能是由于抑制剂共价修饰后P450 2E1蛋白水解降解引起的。DCE是一种有效的、相对无毒的P450 2E1体内和体外抑制剂，比目前使用的其他药物具有更高的选择性。
The effect of trans-1,2-dichloroethylene (DCE), an inhibitor of cytochrome P450 (P450) 2E1, on the catalytic activities and total content of hepatic P450 was determined in vivo and in vitro. Hepatic microsomes were prepared from groups of rats prior to dosing and at 2, 5, 12, and 24 h postdosing, and total P450 content and the activities of P450 1A2, P450 2A1, P450 2B, P450 2C6, P450 2C11, P450 2D1, P450 2E1, and P450 3A were determined. The lowest dose of DCE that yielded maximal inactivation of P450 2E1 was found to be 100 mg/kg. Significant decreases in total content of P450 or the activities of P450 1A2, P450 2A1, P450 2B, P450 2C6, P450 2C11, P450 2D1, and P450 3A were not observed during the 24 h following administration of DCE (100 mg/kg ip), but P450 2E1 activity was diminished about 65% at 2 and 5 h after DCE treatment and returned to control levels at 24 h. Additionally, there was little or no significant effect on the activities of hepatic cytosolic alcohol dehydrogenase or mitochondrial or microsomal aldehyde dehydrogenases 5 h postdosing. DCE showed the same selectivity for P450 inactivation in vitro, and P450 2E1 activity was inhibited by >80% without affecting the other isozymes. However, DCE (5 mM) also proved to be a good competitive inhibitor of the probe activities of P450 1A2 and P450 2C6. The in vivo inhibition of P450 2E1 was accompanied by decreases in the levels of the immunoreactive protein, and an additional immunoreactive band appeared at ca. 30 kDa in the Western blot of microsomes from DCE-treated rats, possibly arising from proteolytic degradation of P450 2E1 protein after covalent modification by the inhibitor. DCE is an effective, relatively nontoxic inhibitor of P450 2E1 in vivo and in vitro that has greater selectivity than other agents currently used.