DRUG METABOLIZING ENZYMES IN ANIMAL MODELS AND HUMAN TISSUE

这个项目是新的，所以工作总结代表计划， 目标和一些初步发现。细胞色素P-450是 催化外源基因的主要单加氧酶系统 化学物质对致突变物和致癌物以及灭活 他们。这个系统会被暴露在 荷尔蒙和外来化学物质。该系统由一个大型的 同工酶的数量，每个同工酶都有自己的底物专一性。一些人 P-450酶是结构性的，有些似乎是 近交系的多态(存在或不存在，活跃或不活跃) 老鼠和人的品系。这种多态可能会导致 某些药物代谢能力的显著差异 (例如，去氢异喹代谢和司马汀的多态 人类的新陈代谢)。针对P-450的抗体和cDNA探针 蛋白质有助于确定化学物质对人体健康的影响。 这些酶并用于研究这些酶的多态。 这些研究的一个目标是检查表型 构成酶P-450G在雄性大鼠和大鼠体内的变异 人类。我们的数据表明，CD大鼠是一个很好的模型 研究这种细胞色素在人类中的多态性。这些研究 发现老鼠可以分为两种不同的表型 含高P-450克(占总P-450的10-20%)或低P-450克 (大于0.5%)。令人惊讶的是，雄性大鼠的这两种表型 似乎含有这种酶的可翻译的mrna 尽管在女性中不存在，这表明这种缺陷 在低表型中可能是缺陷酶或不稳定酶。P-450G 被证明将黄曲霉毒素在重组的 系统。构建了高表型P-1基因的cDNA文库。 450g，以及几个可能的该蛋白的cDNA克隆 已经用抗体进行了选择，并用阳性重新筛选 克隆人。如果人体组织可用，我们计划分析DNA 通过Southern杂交和限制性内切酶分析来确定 一个或多个人类P-450的表型变异性是 与肝脏或肺部肿瘤有关。

This project is new so the summary of work represent plans, objectives and some preliminary findings. Cytochrome P-450 is the principal monooxygenase system which catalyzes foreign chemicals to mutagens and carcinogens as well as inactivating them. This system is perturbed dramatically by exposure to hormones and foreign chemicals. The system consists of a large number of isozymes each with its own substrate specificity. Some P-450 enzymes are constitutive and some appear to be polymorphic (present or absent, active or inactive) in outbred strains of rats and in man. The polymorphisms can result in dramatic differences in the ability to metabolize certain drugs (e.g., a polymorphism for debrisoquine metabolism and sparteine metabolism in man). Antibodies and cDNA probes to the P-450 proteins are useful for determining the effects of chemicals on these enzymes and for studying polymorphisms in these enzymes. One objective of these studies is to examine phenotypic variability of P-450g, a constitutive enzyme, in male rats and humans. Our data suggest that the CD rat is a good model to study polymorphism of this cytochrome in humans. These studies revealed that rats could be divided into two distinct phenotypes containing high P-450g (10-20% of total P-450) or low P-450g (greater than 0.5%). Surprisingly, both phenotypes of male rats appeared to contain a translatable mRNA for this enzyme although it was absent in females suggesting that the defect might be defective or labile enzyme in the low phenotype. P-450g was shown to metabolize aflatoxin to mutagens in a reconstituted system. A cDNA library was constructed from high phenotype P- 450g in rats, and several putative cDNA clones for this protein have been selected with antibody and rescreening with a positive clone. If human tissue is available, we plan to analyze the DNA by Southern blots and restriction analysis to determine whether the phenotypic variability in one or more human P-450s is associated with liver or lung tumors.