ROLE OF NADH--QUINONE REDUCTASE IN ETHANOL METABOLISM

NADH--醌还原酶在乙醇代谢中的作用

• 批准号: 3109291
• 负责人: ROBERT J. RUBIN
• 金额: $ 11.26万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3109291
• 关键词: acetaminophen; alcoholic beverage consumption; alcoholic fatty liver; alcoholism /alcohol abuse; antioxidants; benzene; butylated hydroxytoluene; catalase; enzyme induction /repression; ethanol; ethers; fluorimetry; gas chromatography; genetic strain; glucuronides; glutathione; histology; hydrogen peroxide; isolation perfusion; lipid peroxides; liver cells; liver metabolism; menadione; nicotinamide adenine dinucleotide; oxidoreductase inhibitor; tissue /cell culture; triglycerides

Excessive acute consumption of ethanol causes fatty liver, and inhibits both the oxidation and the glucuronidation of xenobiotics, perhaps by producing excess NADH. Administration of phenolic food additive antioxidants such as BHA (butylated hydroxyanisole) and BHT inhibits the induction of fatty liver by ethanol. BHA is normally metabolized to t-butylquinone (TBQ) and also produces a marked increase of hepatic cytosoe NADH:quinone reductase (QR) activity. We postulate that both the provision of the quinone substrate (TBQ) and the marked elevation of the enzyme activity resulting from the BHA administration may inhibit the (ethanol induced) excessive production of NADH, thus enhancing the rate of ethanol metabolism and preventing the induction of fatty liver and the suppression of glucuronidation. This will be tested by determining the hepatic triglyceride accumulation, level and ratios of NADH and NAD (lactate/pyruvate), rates of ethanol oxidation as well as the glucuronidation of paracetamol and hydroxycoumarin in mice and rats upon acute ethanol administration. We will employ; (a) the inhibitor of cytosolic NADH:quinone reductase (i.e., dicoumarol), (b) inducer of the enzyme (i.e., BHA), and (c) the "Warfarin Resistant" (WR) strain of rats which are deficient in the enzyme. We will also use 3 different mouse strains which differ in both their basal rate of ethanol metabolism as well as in their ability to adapt to acute doses of ethanol. The acute ethanol induced fatty liver and lipid peroxidation in vivo (histology, triglyceride levels, ethane generation), rates for oxidation of ethanol, conjugation of a phenolic drug-like paracetamol, and the levels and ratios of lactate/pyruvate (NADH/NAD) as well as GSH/GSSG will be determined under these conditions using both the isolated hepatocytes and perfused livers. Results obtained by using isolated hepatocytes and perfused livers of these animals will be correlated to those obtained from intact animals. Therefore, this study will attempt to establish the central role of hepatic NADH: quinone reductase (EC 1.6.99.2) both in ethanol and xenobiotic metabolism. Clear understanding of the physiological function of this enzyme may provide means to enhance the metabolism of ethanol as well as to protect against the fatty liver induced by ethanol abuse.

过度急性饮酒会导致脂肪肝，并抑制 外源生物的氧化和葡萄糖醛酸化，可能是通过 产生过量的NADH。酚类食品添加剂的使用 抗氧化剂如BHA(丁基羟基苯甲醚)和BHT可抑制 乙醇诱导脂肪肝的实验研究。BHA通常被代谢成 叔丁基醌(TBQ)，并产生明显增加的肝细胞胞质 NADH：苯醌还原酶(QR)活性。我们假设，这两项规定 对苯二酚底物(TBQ)和酶的显著升高 BHA给药产生的活性可能会抑制(乙醇 诱导)NADH的过度产生，从而提高乙醇的产率 代谢与预防脂肪肝的诱导与抑制 葡萄糖醛酸化作用的结果。 这一点将通过确定肝脏甘油三酯的蓄积来进行测试， NADH和NAD(乳酸/丙酮酸)的水平和比率，乙醇的比率 扑热息痛和羟基香豆素的氧化及葡萄糖醛酸化 在小鼠和大鼠急性乙醇注射时。我们将聘用：(A) 胞内NADH的抑制剂：苯醌还原酶(即双香豆酚)，(B) 酶的诱导剂(即BHA)，以及(C)抗华法林(WR) 缺乏这种酶的大鼠的品系。我们还将使用3 不同品系的小鼠，它们的基础酒精含量不同 他们的新陈代谢以及适应急性剂量乙醇的能力也是如此。 急性酒精性脂肪肝与体内脂质过氧化反应 (组织学，甘油三酯水平，乙烷生成)，氧化速率 乙醇、类酚类药物扑热息痛的结合物及其含量 乳酸/丙酮酸(NADH/NAD)和GSH/GSSG的比率将为 在这些条件下使用分离的肝细胞和 灌流的肝脏。使用分离的肝细胞和 这些动物的灌流肝脏将与从 完好无损的动物。 因此，本研究试图确立肝脏的核心作用。 NADH：乙醇和外源生物中的苯醌还原酶(EC 1.6.99.2) 新陈代谢。对此的生理功能有清晰的认识 酶可以提供增强乙醇新陈代谢的手段以及 防止因滥用酒精而导致的脂肪肝。