CAFFEINE AS MARKER OF CYTOCHROME P4502E1

最近，我们发现细胞色素P450 2E1(细胞色素P450 2E1)，一种乙醇- 诱导性细胞色素在咖啡因中起着重要作用 生物转化，除了CYP1A2，特别是在形成 茶碱和可可碱。同时发现了一个 22例儿童尿中咖啡因代谢物谱显著改变 确认为酗酒者。这些观察结果促使这一提议进行测试 咖啡因代谢物模式的改变作为一项指标的可行性 类似于使用咖啡因代谢物的细胞色素P450酶2活性的标志物 比值作为细胞色素P450 1A2活性的指标。 CYP2E1已成为众多调查的目标，因为它 乙醇消耗的诱导性及其预活化能力 致癌物质(例如亚硝胺)。因为没有引用方法，所以 体内细胞色素P450-2E_1活性测定方法的建立 体内试验必须依赖于体外研究的结果。使用PURE 细胞色素CYP1A2和CYP2E1来自痘苗病毒CDNA的表达，我们计划 确定特定咖啡因代谢物的模式与 以细胞色素P450_2_1/细胞色素P450_2_2活性比值为指标。获得的结果 然后，将通过使用人类肝脏微体来验证纯酶。 提出了一种评价细胞色素P450-2E_1活性的指标 其中，22个酗酒者的价值是27个人的10倍 控制。我们建议使用代谢物的结果来评估这一指标 125名确诊酗酒者已采集尿样的特征分析 和125个对照。此外，代谢物的模式和比例将 经过仔细审查，以搜索其他CYP2E1指数。既然大家都知道酗酒者 要具有高度诱导的CYP2E1活性，参数显示为 将评估酗酒者和对照组之间的差异。

Recently, we showed that CYP2E1 (cytochrome P450 2E1), an ethanol- inducible cytochrome, plays an important role in caffeine biotransformation, in addition to CYP1A2, especially in the formation of theophylline and theobromine. There was a concurrent discovery of a significant shift of caffeine metabolite profile in the urine of 22 confirmed alcoholics. These observations prompted this proposal to test the feasibility of using the change of caffeine metabolite pattern as a marker of CYP2E1 activity, analogous to the use of a caffeine metabolite ratio as an index for CYP1A2 activity. CYP2E1 has become the target of numerous investigations because of its inducibility by ethanol consumption and its capacity to bioactivate pre- carcinogens (e.g. nitrosamines). Because there is no reference method for the in vivo estimation of CYP2E1 activity, development of methods for in vivo tests must rely on results from in vitro studies. Using pure cytochromes CYP1A2 and CYP2E1 from Vaccinia CDNA expression, we plan to establish that the pattern of specific caffeine metabolites is associated with the ratio of CYP2E1 to CYP1A2 activity. Results obtained with the pure enzymes will then be verified by using human liver microsomes. An index for CYP2E1 activity was proposed to estimate CYP2E1 activity where it yielded a value 10 times higher for 22 alcoholics compared to 27 controls. We proposed to assess this index using results of metabolite profiling of already collected urine samples from 125 confirmed alcoholics and 125 controls. In addition, metabolite patterns and ratios will be scrutinized to search for other CYP2E1 indices. Since alcoholics are known to have highly induced CYP2E1 activity, parameters that show large differences between alcoholics and controls will be evaluated.