ACETAMINOPHEN BINDING/HEPATOCYTE HOMEOSTASIS-TOXICITY

对乙酰氨基酚（APAP）是一种广泛使用的，安全的， 止痛药，当服用过量时，会导致严重的 肝坏死 肝毒性是由于微粒体 将APAP活化为亲电体， 谷胱甘肽储备，然后共价结合到关键细胞 件. APAP或其代谢物 引发并延续病理过程， 细胞死亡仍然未知。 最近对APAP的研究表明， 证明了选择性早期共价结合到单个 微粒体蛋白带。 APAP还导致超微结构 以及内质网，线粒体， 溶酶体和质膜。 的关系 蛋白质的选择性芳基化和观察到的细胞效应 APAP尚未建立。 拟议的研究将 着重于共价结合的性质和重要性， APAP诱导的肝毒性中的特异性蛋白质。 这将是 通过研究以下关系来解决：1）修改 通过选择性共价结合和/或 氧化，2）特定细胞器功能的改变，以及3） 肝毒性的发生和发展。 设计 将涉及协调小鼠肝细胞的研究， 在小鼠中进行体内研究。 我们已经开发了一个 亲和纯化的抗体，其对共价结合的 APAP。 它将广泛用于拟议的研究， 允许鉴定阿帕结合的细胞器蛋白 以及确定APAP的特异性 结合和自我平衡过程的改变，以及 改变与肝毒性的关系。 肝 损伤将通过生物化学、组织病理学和 超微结构上。 毒性的程度将因 仔细选择APAP剂量和时间组合以及 通过实验性的增强和对抗。 这将 允许评估共价结合的重要性， 改变蛋白质巯基水平， 细胞器在APAP肝毒性中的作用。 澄清 《亚太行动计划》引起的变化的性质和 改变了对有毒物质至关重要的人类稳定功能， 这一过程将使人们更清楚地了解生物化学 APAP肝毒性的潜在机制， 作用肝毒素 这将有助于最终 发展合理的替代疗法来预防。

Acetaminophen (APAP) is a widely used, safe, antipyretic analgesic which, when taken in excessive doses, causes severe hepatic necrosis. Hepatotoxicity is the result of microsomal activation of APAP to an electrophile which first depletes glutathione reserves and then covalently binds to critical cell components. The mechanism whereby APAP or its metabolite initiate and perpetuate the pathological sequence which results in cell death remains unknown. Recent studies with APAP have demonstrated selective early covalent binding to a single microsomal protein band. APAP also resulted in ultrastructural and biochemical changes in endoplasmic reticulum, mitochondria, lysosomes and plasma membrane. The relationship between the selective arylation of proteins and the observed cellular effects of APAP has not yet been established. The proposed studies will focus upon the nature and importance of covalent binding to specific proteins in APAP-induced hepatotoxicity. This will be addressed by studying the relationships among 1) the modification of specific proteins by selective covalent binding and/or oxidation, 2) the alterations in specific organelle functions, and 3) the initiation and progression of the hepatotoxicity. The design will involve coordination of studies of mouse hepatocytes, in culture with in vivo studies in mice. We have developed an affinity purified antibody which is specific for covalently bound APAP. It will be used extensively in the proposed studies to permit identification of organelle proteins to which APA binds and determination of the relationship between APAP's specific binding and the alterations in homeostatic processes as well as the relationship of the alterations to the hepatotoxicity. Liver damage will be verified biochemically, histopathologically and ultrastructurally. The degree of toxicity will be varied through careful selection of APAP dosage and time combinations as well as through experimental enhancement and antagonism. This will permit assessment of the importance of covalent binding and altered protein sulfhydryl levels to the derangement of specific organelle functions in APAP hepatotoxicity. Clarification of the nature of the APAP induced changes and identification of the altered homcostatic functions which are critical to the toxic process will permit a clearer understanding of the biochemical mechanisms underlying the hepatotoxicity of APAP and similarly acting hepatotoxins. This will facilitate the eventual development of rational alternative therapies for its prevention.