EFFECTS OF DISULFIRAM ON HEPATIC P450IIE1, OTHER MICROSOMAL-ENZYMES, AND HEPATOTOXICITY IN RATS
EFFECTS OF DISULFIRAM ON HEPATIC P450IIE1, OTHER MICROSOMAL-ENZYMES, AND HEPATOTOXICITY IN RATS
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DOI：
10.1016/0041-008x(91)90125-x
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发表时间：
1991-04-01
影响因子：
3.8
通讯作者：
YANG, CS
中科院分区：
文献类型：
--
作者：
BRADY, JF;XIAO, F;YANG, CS
双硫仑广泛用于酒精滥用的避免治疗，已被证明对化学诱导的毒性和致癌作用具有保护作用。这项工作的目的是阐明这种保护作用的生化机制，通过检查其对细胞色素P450 IIE 1和其他相关的微粒体酶活性的影响。当大鼠灌胃给予一定剂量的双硫仑时，观察到N-亚硝基二甲胺（NDMA）脱甲基酶活性非常迅速地降低，可能是由于P450 IIE 1失活所致。在接受双硫仑后18小时观察到微粒体膜P450 IIE 1蛋白的丢失，但在治疗后的前5小时内未观察到。另一方面，P450 IIB 1在双硫仑处理后15至72小时之间显著诱导。然而，处理仅引起其他一些P450同工酶的中度变化。二硫化碳是双硫仑的一种假定代谢物，对P450 IIE 1产生类似的作用，但持续时间较短。然而，二硫化碳不诱导P450 IIB 1。二乙基二硫代氨基甲酸酯是双硫仑的还原产物，是体外P450 IIE 1活性的抑制剂，在与微粒体预孵育后，它会产生NDMA脱甲基酶活性的NADPH依赖性失活。结果表明，双硫仑的这种或其他代谢产物是P450 IIE 1的抑制剂，并负责体内P450 IIE 1的失活。双硫仑预处理可阻断NDMA或CCl 4对大鼠的肝毒性。目前的工作表明，P450 IIE 1被双硫仑抑制和失活，这种机制可以解释双硫仑对化学诱导的毒性和致癌作用的许多报道的抑制作用。
Disulfiram, widely used in avoidance therapy for alcohol abuse, has been shown to have protective effects against chemically induced toxicity and carcinogenesis. The purpose of this work was to elucidate the biochemical mechanisms of this protective action by examining its effects on cytochrome P450IIE1 and other related microsomal enzyme activities. When a dose of disulfiram was given intragastrically to rats, a very rapid decrease of N-nitrosodimethylamine (NDMA) demethylase activity, possibly due to the inactivation of P450IIE1, was seen. The loss of P450IIE1 protein from the microsomal membrane was observed at 18 hr after receiving disulfiram, but not within the first 5 hr after the treatment. P450IIB1, on the other hand, was induced markedly between 15 and 72 hr after the disulfiram treatment. The treatment, however, caused only moderate changes in some other P450 isozymes. Carbon disulfide, a putative metabolite of disulfiram, produced similar effects on P450IIE1, but with shorter duration. Carbon disulfide, however, did not induce P450IIB1. Diethyldithiocarbamate, a reductive product of disulfiram, was an inhibitor of P450IIE1 activity in vitro, and upon preincubation with microsomes, it produced an NADPH-dependent inactivation of NDMA demethylase activity. The results suggest that this or other metabolites of disulfiram are inhibitors of P450IIE1 and are responsible for the inactivation of P450IIE1 in vivo. Hepatotoxicity of NDMA or CCl4in rats was blocked by pretreatment with disulfiram. The present work demonstrates that P450IIE1 was inhibited and inactivated by disulfiram, and this mechanism can account for many of the reported inhibitory actions of disulfiram against chemically induced toxicity and carcinogenesis.