NADPH-DEPENDENT METABOLISM OF ARACHIDONIC ACID

脂类作为细胞功能和功能的重要介质的作用 在过去的几年里，生理学已经变得越来越明显。 花生四烯酸是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意义 生物活动，并被牵连到 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，可用于氧化代谢。 花生四烯酸，几个小组的研究表明 这一重要的酶系统在生物活性中的作用 花生四烯酸。NADPH依赖的环氧合酶反应 催化四个区域异构体的立体专一性形成 环氧二十碳三烯酸(EETs)。外星人已经被记录在案 作为几个哺乳动物器官的内源性成分以及 人类的尿液。除了它们的体外血管活性 EETs在肾脏生理学中的特性和作用 几种多肽荷尔蒙释放的体外刺激。 值得注意的是，EET刺激的激素释放和 细胞钙代谢的变化已经被记录在案。这个 两种新型磷脂酰肌醇在大鼠肝脏中的存在 (EET-PI)和含酯化EET的乙醇胺(EET-PE) 部分已被描述过。定量分析表明， EET-PI的摩尔分数是EET-PE的7-8倍。 我们认为，必须在#年分析这一发现的重要性。 肌醇脂类在受体介导中的关键作用 信号转导、钙动员与秒的产生 信使，以及所描述的EETs的生物学活性 作为环氧合酶反应在生成过程中的可能作用 独特的生物活性脂水池。 通过使用稳定的放射性同位素和既定的提取方法， 高效液相色谱和谷胱甘肽程序，我们计划1)表征分子 大鼠肝脏甘油脂的结构，2)研究 花生四烯基甘油酯环氧化反应的酶学研究 合成EETs酯化反应的酶学，4)研究 磷脂酶C对EET-PI的降解；5)利用速率 肝细胞作为上述反应的综合模型 以开始了解它们在细胞功能中可能扮演的角色。

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.