DIHYDRODIOL DEHYDROGENASE AND PAH DETOXIFICATION

此应用程序请求支持研究生涯 发展奖，以表彰继续系统地研究 二氢二醇脱氢酶在解毒中的作用 多环芳烃的近致癌物和终极致癌物 碳氢化合物（PAH）。 研究项目包括化学， 生物化学、细胞和人体研究，旨在提供 关于这种酶在PAH代谢中的作用的信息。 我们已经证明，均相二氢二醇脱氢酶 氧化多种非K区-反式 致癌PAH的二氢二醇与相应的邻位- 醌类，其可以巯基乙醇加合物的形式被捕获。 到 获得关于这种替代途径的信息， 致癌物代谢，非K-区邻位的反应性， 将检查醌产物对细胞亲核试剂的作用， 湾区甲基化对反应性的影响将是 测定，谷胱甘肽的能力，以提高酶的速度 反式二氢二醇的氧化， 产品将被评估，推定醌的结构- 谷胱甘肽加合物将被阐明，这些能力 邻醌产品作为底物的高度纯化 大鼠肝谷胱甘肽转移酶的制备将 测定 均质二氢二醇脱氢酶参与 最终的致癌物质代谢将探索使用 萘和菲的稳定的反二醇环氧化物， 苯并（a）芘（BP）的反二醇环氧化物作为底物。 细胞研究将利用大鼠肝癌的发现， 细胞系（H-4 II-e）含有二氢二醇脱氢酶， 对吲哚美辛和6- 醋酸甲羟孕酮 通过研究 在这些细胞中BP的（3 H）-7，8-反式-二氢二醇， 如果没有这些药物，二氢二醇的作用 脱氢酶对全细胞中PAH的解毒作用将是 评估。 如果这种酶在这些药物中起重要作用， 应该评估抗二醇环氧化物和BP-DNA加合物的水平。 确定二氢二醇脱氢酶是否在PAH中发挥作用 在人体代谢中，肝脏尸检样本将进行B分析， 这种酶的活性，活动将被分开， 色谱和氧化反式-7，8- BP的二氢二醇将被表征。

This application requests support for a Research Career Development Award for continuation of a systematic study of the role of dihydrodiol dehydrogenase in the detoxification of proximate and ultimate carcinogens of polycyclic aromatic hydrocarbons (PAH). The research programs includes chemical, biochemical, cellular and human studies designed to provide information on the role of this enzyme in PAH metabolism. We have shown that the homogeneous dihydrodiol dehydrogenase from rat liver cytosol oxidizes a variety of non-K-region-trans dihydrodiols of carcinogenic PAH to the corresponding ortho- quinones which can be trapped as mercaptoethanol adducts. To obtain information on this alternative pathway of proximate carcinogen metabolism, the reactivity of non-K-region ortho- quinone products towards cellular nucleophiles will be examined, the influence of bay-region methylation on reactivity will be determined, the ability of glutathione to enhance enzymatic rates of trans-dihydrodiol oxidation by trapping the ortho-quinone products will be assessed, structures of putative quinone- glutathione adducts will be elucidated, and the ability of these ortho-quinone products to act as substrates for highly purified preparations of rat liver glutathione transferases will be determined. The involvement of the homogeneous dihydrodiol dehydrogenase in ultimate carcinogen metabolism will be explored by using the stable anti-diol-epoxides of naphthalene and phenanthrene and the anti-diol epoxide of benzo(a)pyrene (BP) as substrates. Cellular studies will exploit the findings that the rat hepatoma cell line (H-4II-e) contains dihydrodiol dehydrogenase that is exquisitely sensitive to inhibition by indomethacin and 6- medroxyprogesterone acetate. By studying the metabolism of the (3H)-7,8-trans-dihydrodiol of BP in these cells, in the presence and absence of these drugs, the contribution of dihydrodiol dehydrogenase to the detoxification of PAH in whole cells will be assessed. If this enzyme plays a significant role these drugs should evaluate levels of anti-diol epoxides and BP-DNA adducts. To determine if dihydrodiol dehydrogenase plays a role in PAH metabolism in humans, liver autopsy samples will b analyzed for this enzyme activity, activities will be separated by chromatography and isozymes which oxidize the trans-7,8- dihydrodiol of BP will be characterized.