INTERACTION OF ETHANOL WITH HEPATIC MICROSOMES

在建立微粒体乙醇氧化系统（MEOS）后， 不同于醇脱氢酶（ADH）和过氧化氢酶的实体， 申请人现在希望解决所涉及的机制的问题， MEOS在乙醇代谢中的作用。 具体地说， 将从大鼠中纯化乙醇诱导形式的细胞色素P-450， 鹿鼠和狒狒 我们将表征纯化的蛋白质， 分子量、光谱、底物特异性和肽 映射. 尽管这些细胞的细胞色素P-450存在已知的差异， 物种，我们希望找到一个共同的变化，可能会揭示一些光 乙醇诱导的改变的性质及其对乙醇的特异性 基板。 我们还将确定羟基自由基在多大程度上 参与由乙醇诱导形式的 细胞色素P-450 此外，我们将评估 细胞色素P-450导致其它底物代谢改变， 类固醇激素和视黄酸（维生素A的重要形式， 酒精的营养状况），致癌物质（可能的 的重要性增加癌症的发病率在酒精）和 工业溶剂和常用药物的肝毒性增强， 包括促进脂质过氧化（与发病机制相关 酒精性肝损伤）。 评估中海观测系统的相对重要性， 以确定它对代谢耐受性的贡献， 发展后，慢性乙醇消费，我们将比较的命运 (3H)从ADH+和ADH-分离的肝细胞中的木糖醇和（H3）乙醇 鹿鼠 在同一实验模型中，我们将研究同位素效应 以区分MEOS从其他醇氧化 系统，无论是在分离的肝细胞和体内。 我们的广泛目标 这项研究有助于我们了解酗酒者与 在生化方面，非酒精性;特别是我们计划确定， 酒精对微粒体细胞色素P-450的影响程度 消费改变了酒精对内源性和 外源性化合物可能影响酒精诱导的肝脏 病理学及其预防和治疗。

After having established the microsomal ethanol oxidizing system (MEOS) as an entity distinct from alcohol dehydrogenase (ADH) and catalase, the applicant now wishes to address the question of the mechanism involved and the role of MEOS in ethanol metabolism in vitro and in vivo. Specifically, the ethanol-induced form of cytochrome P-450 will be purified from rats, deermice and baboons. We will characterize the purified protein(s) in terms of molecular weight, spectra, substrate specificity and peptide mapping. Despite known differences in the cytochrome P-450 of these species, we hope to find a common change that may shed some light on the nature of the ethanol-induced alteration and its specificity for ethanol as a substrate. We will also determine to what extent hydroxyl radicals are involved in ethanol oxidation mediated by the ethanol-induced form of cytochrome P-450. Furthermore, we will assess whether the changes in cytochrome P-450 result in altered metabolism of other substrates such as steroid hormones and retinoic acid (a form of vitamin A of significance for the nutritional status of the alcoholic), carcinogens (of possible importance for the enhanced incidence of cancers in the alcoholic) and in enhanced hepatotoxicity of industrial solvents and commonly used drugs, including promotion of lipid peroxidation (of relevance to the pathogenesis of alcoholic liver injury). To assess the relative importance of MEOS and to determine how much it contributes to the metabolic tolerance that develops after chronic ethanol consumption, we will compare the fate of (3H) xylitol and (H3) ethanol in hepatocytes isolated from ADH+ and ADH- deermice. In the same experimental model we will study the isotope effect of deuterium to differentiate MEOS from the other alcohol oxidizing systems, both in isolated hepatocytes and in vivo. The broad aim of our study is to contribute to our understanding of how alcoholics differ from non-alcoholics in biochemical terms; specifically we plan to determine to what extent changes produced in the microsomal cytochrome P-450 by alcohol consumption alters the response of the alcoholic to endogenous and exogenous compounds in a way that may affect alcohol induced liver pathology, its prevention and its treatment.