NADPH-DEPENDENT METABOLISM OF ARACHIDONIC ACID

花生四烯酸的 NADPH 依赖性代谢

• 批准号: 3293757
• 负责人: JORGE CAPDEVILA
• 金额: $ 18.25万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-06-01 至 1993-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3293757
• 关键词: NAD(H) phosphate; arachidonate; biological signal transduction; calcium metabolism; cytochrome P450; enzyme reconstitution; epoxides; fatty acid metabolism; gas chromatography mass spectrometry; glutathione transferase; high performance liquid chromatography; hydrolysis; laboratory rat; lipid metabolism; liver cells; microsomes; oxygenases; peptide hormone metabolism; phosphatidylinositols; phospholipase C; radiotracer; stereoisomer; unspecific monooxygenase

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.

脂质作为细胞功能的重要介质和 在过去的几年中，生理学变得越来越明显。 哺乳动烯酸通过哺乳动物细胞通过 “蛛网级联”到各种重要的产品 生物活动，与 许多疾病状态的病理生理学。 微粒体细胞色素p- 450是用于氧化代谢的活性催化剂 花生四烯酸以及来自几组的研究表明 这种重要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 催化四个区域异构体的立体特异性形成 环氧树钠酸（EET）。 Eets已记录 作为几个哺乳动物器官的内源成分 人类尿液。 除了体外血管活性 肾脏生理学的特性和影响，EET有效 释放几种肽激素的体外刺激。 值得注意的是，EET刺激激素释放与 细胞钙代谢的变化已记录在记录中。 这 在两个新型磷脂酰肌醇池的大鼠肝脏中的存在 （EET-PI）和乙醇胺（EET-PE），含有酯化的EET 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关键作用的术语 信号转导，钙动员和第二次产生 信使，也描述的Eets的生物学活动 作为环氧化酶反应在发电中的可能作用 独特的生物活性脂质池。 通过使用稳定和放射性同位素并确定提取， HPLC和GSH程序，我们计划1）表征分子 大鼠肝脏中存在的甘油脂质的结构，2）研究 蛛网膜氧化酶的酶学，3）研究 合成Eets酯化的酶学，4）研究 磷脂酶C对EET-PI的水解和5）利用大鼠 肝细胞作为上述反应的集成模型 开始了解它们在细胞功能中的可能作用。