ETHANOL INDUCTION OF UDP-GLUCURONYLTRANSFERASE

酒精对药物在体内的新陈代谢有两种影响 主要方法：1)给药时降低代谢 与酒精同时，从而增强药物的作用； 2)当摄入更大剂量的乙醇时增加新陈代谢 (如酗酒者)在服药前的较长时间内， 从而由于新陈代谢更快而降低药物的疗效。它 是我们将在这项工作中研究的这两个效应中的第二个。这个 通常被接受的原因是观察到的药物代谢增加 酒精是诱导细胞色素P-450单加氧酶的酶。 然而，另一种重要的代谢酶，UDP-葡萄糖醛酸基转移酶 (GT)，也可由乙醇诱导。GT诱导的程度 乙醇，以及这种现象对动物药物代谢的影响 而人类并没有得到实质性的解决。 我们证明了以对硝基苯酚为底物的GT活性是 在兔肝微粒体中大量诱导。这项研究将 通过解决两个主要问题来扩展前面的工作：1)做 乙醇诱导兔体内GT产生独特的同工酶，其物理机制是什么？ 以及该同工酶的催化性质；以及2)在 乙醇相关药物处置的体内药代动力学变化 GT活性的诱导？ 我们将用GT同工酶的纯化来回答第一个问题 从乙醇处理过的动物的兔肝微粒体中提取。我们 将通过与其他方法的比较来鉴定乙醇诱导的GT同工酶 纯化的siozyme的凝胶电泳迁移率(分子 重量)、氨基酸组成、催化专一性 底物和催化效率(Km和Vmax)。第二个问题 将通过在兔子体内测定酒精后的变化来回答 消耗药代动力学参数(血浆清除量、半衰期、 AUC等)几种药物(奥沙西潘、劳拉西潘、地西潘和苯妥英钠) 主要通过葡萄糖醛酸化物结合排泄。 因此，这项工作不仅将建立特定的生物化学基础 乙醇诱导的GT，但也将诱导现象与 临床情况。我们的研究将增加我们对 酒精中毒对药物代谢的影响，从而对 这些药物对酗酒者的治疗作用。

Alcohol has been shown to affect the metabolism of drugs in the body in two major ways: 1) descreasing the metabolism when the drug is given simultaneously with alcohol, thereby potentiating the action of the drug; and 2) increasing the metabolism when larger doses of ethanol are ingested (as in alcoholics) over lengthy time periods prior to taking the drug, thereby decreasing the efficacy of the drug due to faster metabolism. It is the second of these two effects that we will study in this work. The usually accepted reason for the increased metabolism of drugs observed in alcoholics is the induction of the cytochrome P-450 monooxygenase enzymes. However, another important metabolism enzyme, UDP-glucuronyltransferase (GT), may also be induced by ethanol. The extent of GT induction by ethanol, and the effect of this phenomenon on drug metabolism in animals and man has not been substantially addressed. We have demonstrated that GT activity with p-nitrophenol as substrate is substantially induced in rabbit hepatic microsomes. This research will extend the previous work by addressing two major questions: 1) does ethanol induce a unique isozyme of GT in rabbits, and what are the physical and catalytic properties of this isozyme; and 2) what are the specific in vivo pharmacokinetic changes in drug disposition associated with ethanol induction of GT activity? We will answer the first question with the purification of the GT isozyme from rabbit hepatic microsomes from animals pretreated with ethanol. We will characterize the ethanol-induced GT isozyme by comparison with other purified siozymes in respect to gel electrophoretic mobility (molecular weight), amino acid composition, catalytic specificity for several substrates, and catalytic efficiency (Km and Vmax). The second question will be answered by determining in rabbit the changes after alcohol consumption in pharmacokinetic parameters (plasma clearance, half-life, AUC, etc.) of several drugs (oxazepam, lorazepam, diazepam, and phenytoin) that are primarily excreted via glucuronide conjugation. This work will thus establish not only the specific biochemical basis for GT induction by ethanol, but also correlate the induction phenomenon to the clinical situation. Our research will increase our knowledge of the effects of alcoholism on the metabolism of drugs, and therefore on the therapeutic use of these drugs with alcoholics.