NADPH-DEPENDENT METABOLISM OF ARACHIDONIC ACID

脂质作为细胞功能重要介质的作用， 在过去的几年里，生理学变得越来越明显。 花生四烯酸由哺乳动物细胞通过 “花生四烯酸级联”对多种产品具有重要作用 生物活动，并已被牵连在 许多疾病状态的病理生理学。 微粒体细胞色素P- 450是一种活性催化剂， 花生四烯酸，来自几个小组的研究表明， 这种重要的酶系统在生物活化中的作用 花生四烯酸 NADPH依赖性环氧酶反应 催化四种区域异构体的立体特异性形成 环氧二十碳三烯酸（ESTs）。 据记载， 作为几种哺乳动物器官的内源性成分， 人类的尿液 除了它们的体外血管活性外， 在肾脏生理学中的性质和作用，Ehrs是有效的， 用于释放几种肽激素的体外刺激物。 值得注意的是，EET刺激的激素释放和 细胞钙代谢的变化已被记录。 的 大鼠肝脏中存在两种新的磷脂酰肌醇库 （EET-PI）和含有酯化的EET的乙醇胺（EET-PE） 已经描述了部分。 定量分析表明， EET-PI的摩尔分数是EET-PE的7-8倍。 我们认为必须分析这一发现的重要性 肌醇脂质在受体介导的 信号转导、钙动员和第二代 信使，描述的生物活动的埃塞尔比亚以及 由于环氧合酶反应在生成 独特的生物活性脂质池。 通过使用稳定的放射性同位素和已建立的提取， HPLC和GSH程序，我们计划1）表征分子 存在于大鼠肝脏中的甘油脂的结构，2）研究 花生四烯酸甘油酯环氧化的酶学研究; 酯化反应的酶学研究; 4）研究了酯化反应的酶学性质， 磷脂酶C水解EET-PI，和5）利用大鼠 肝细胞作为上述反应的综合模型， 来开始了解它们在细胞功能中的可能作用。

The role of lipids as important mediators of cell function and physiology has become increasingly evident in the last few years. Arachidonic acid is metabolized by mammalian cells through the "arachidonate cascade" to a variety of products with important biological activities and which have been implicated in the pathophysiology of many disease states. Microsomal cytochrome P- 450 is an active catalyst for the oxygenated metabolism of arachidonic acid, and studies from several groups have suggested a role for this important enzyme system in the bioactivation of arachidonic acid. The NADPH-dependent epoxygenase reaction catalyzes the stereospecific formation of four regioisomeric epoxyeicosatrienoic acids (EETs). The EETs have been documented as endogenous constituents of several mammalian organs as well as of human urine. In addition to their in vitro vasoactive properties and effects in renal physiology, the EETs are potent in vitro stimuli for the release of several peptide hormones. Significantly, a link between EET stimulated hormone release and changes in cell calcium metabolism has been documented. The presence in rat liver of two novel pools of phosphatidylinositol (EET-PI) and ethanolamine (EET-PE) containing an esterified EET moiety has been described. Quantitative analysis showed that the mole fraction of EET-PI is 7-8 times that of EET-PE. We believe that the importance of this finding must be analyzed in terms of the pivotal role of inositol lipids in receptor mediated signal transduction, calcium mobilization and generation of second messengers, the described biological activities of the EETs as well as the possible role of the epoxygenase reaction in the generation of unique pools of bioactive lipids. By the use of stable and radioisotopes and established extraction, HPLC and GSH procedures, we plan to 1) characterize the molecular structure of the glycerolipids present in rat liver, 2) study the enzymology of epoxidation of arachidonylglycerolipids, 3) study the enzymology of esterification of synthetic EETs, 4) study the hydrolysis of EET-PI by phospholipase C, and 5) utilize rat hepatocytes as an integrated model of the above reactions in order to begin to understand their possible role in cell function.