CHARACTERIZATION OF HUMAN LIVER CYTOCHROMES P450

人肝细胞色素 P450 的表征

• 批准号: 3452824
• 负责人: JUDY L RAUCY
• 金额: $ 10.65万
• 依托单位: UNIVERSITY OF NEW MEXICO
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-09-01 至 1993-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3452824
• 关键词: acetaminophen; alcoholic beverage consumption; alcoholism /alcohol abuse; aminoacid analyzer; biopsy; cimetidine; cytochrome P450; drug metabolism; enzyme induction /repression; enzyme mechanism; enzyme reconstitution; ethanol; flavones; gel electrophoresis; hepatotoxin; high performance liquid chromatography; human tissue; laboratory mouse; liver metabolism; microsomes; monoclonal antibody; toxicant interaction; toxin metabolism

The main goals of this research project are to identify human liver cytochromes P-450 involved in the activation of acetaminophen to a reactive intermediate. Studies in this proposal will focus on modulators of cytochrome P-450 catalyzed acetaminophen activation. We will examine the mechanisms involved in ethanol induction, 7,8 benzoflavone (ANF) stimulation and cimetidine inhibition. Ethanol potentiation of acetaminophen hepatotoxicity has been documented in both human and animal studies, suggesting that modulation by induction of the ethanol enzyme is the mechanism by which potentiation of toxicity occurs. In addition, modulators may be used as a means of identifying isozymes of cytochrome P-450. The use of ANF as a stimulator of acetaminophen activation has allowed us to identify the presence of at least two cytochromes P-450 involved in this reaction in human liver. In addition, we propose to purify the human liver cytochromes and prepare monoclonal antibodies which may be employed in defining which population of individuals may be more susceptible to hepatotoxicity from large doses of acetaminophen. The high degree of specificity exhibited by these antibodies will allow them to be used as specific inhibitors in the acetaminophen assay to verify the role of the cytochromes in the metabolism of acetaminophen. Using needle biopsy samples from individuals exposed to various quantities of ethanol for different lengths of time and subjecting the samples to immunoblots developed with the antibody to the human ethanol P-450, should provide information about induction and de-induction of the enzyme. Finally, we will examine whether human kidney microsomes contribute to acetaminophen activation and identify, by use of the monoclonal antibodies prepared to the liver cytochromes, the cytochromes P-450 which may be involved. Thus, these studies provide a two-fold purpose. First, in identifying human liver cytochromes P-450 that may produce activation of acetaminophen and mechanisms of modulating their metabolism to prevent hepatotoxicity and second, to determine the quantity of ethanol and duration of exposure required for induction of human liver ethanol P-450.

该研究项目的主要目标是识别人类 肝细胞色素 P-450 参与激活 对乙酰氨基酚转化为反应中间体。 这方面的研究 提案将重点关注细胞色素 P-450 催化的调节剂 对乙酰氨基酚激活。 我们将研究机制 参与乙醇诱导、7,8苯并黄酮 (ANF) 刺激 和西咪替丁抑制作用。 对乙酰氨基酚的乙醇增效作用 人类和动物的肝毒性均已被记录 研究表明，通过诱导乙醇进行调节 酶是增强毒性的机制 发生。 此外，调制器可以用作一种手段 鉴定细胞色素 P-450 的同工酶。 使用 ANF 作为 对乙酰氨基酚激活的刺激剂使我们能够识别 至少有两种细胞色素 P-450 参与此过程 人肝脏中的反应。 此外，我们建议净化 人肝细胞色素并制备单克隆抗体 可以用来定义哪些人群 可能更容易受到大剂量的肝毒性 对乙酰氨基酚。 这些表现出高度的特异性 抗体将使它们能够用作特定的抑制剂 对乙酰氨基酚测定验证细胞色素在 对乙酰氨基酚的代谢。 使用来自以下组织的针吸活检样本 个体因不同原因接触不同量的乙醇 时间长度并对样品进行免疫印迹 用人乙醇 P-450 抗体开发的，应该 提供有关感应和去感应的信息 酶。 最后，我们将检查人体肾脏是否 微粒体有助于对乙酰氨基酚的激活并识别， 通过使用针对肝脏制备的单克隆抗体 细胞色素，可能涉及细胞色素P-450。 因此，这些研究提供了双重目的。 首先，在 鉴定可能产生的人类肝细胞色素 P-450 对乙酰氨基酚的激活及其调节机制 代谢以防止肝毒性，其次确定 所需的乙醇量和暴露时间 人肝乙醇 P-450 的诱导。