DIHOMO-Y-LINOLENIC ACID METABOLITES LIPOXYGENASE PATHWAY

花生四烯酸是合成脂肪酸的主要脂肪酸前体， 生物活性类花生酸。 类二十烷酸的关键作用， 生理和免疫机制的调节剂是有据可查的， 因此，控制它们的水平在治疗中具有很大的意义。 预防许多疾病。 其中一个很有前途的策略是， 背景是通过提供替代的抗氧化剂来调节类二十烷酸的产生。 通过饮食控制氧化代谢的底物。 最近的注意力已经集中在二高-γ- 亚麻酸（DHGLA），因为它被认为是负责代理 对于报春花油在治疗 各种疾病。 这些包括炎症过程，皮肤病， 免疫紊乱、经前疼痛和恶性肿瘤。 拟议研究的总体目标是了解 DHGLA的有益营养作用的潜在机制。 的 研究是基于这样一个前提，即膜花生四烯酸的替代 DHGLA导致花生四烯酸衍生的 类花生酸水平。 待检验的总体假设是DHGLA作用于 作为氧化酶的竞争性抑制剂， 花生四烯酸底物，DHGLA的氧化产物是 在生物学上不如花生四烯酸代谢物有效， 在某些情况下，前一种化合物作为细胞的拮抗剂， 类花生酸受体。 拟议项目的中心目标是 生产和表征从DHGLA衍生的代谢产物， 5-脂肪氧合酶途径，并测试这些相对生物活性 已知在免疫和生理功能测定中的分子 由花生四烯酸的脂氧合酶产物调节。 该假设将通过许多体外实验来解决， 具体目标如下：1）合成和表征 的DHGLA的初级和次级氧化产物， 超纯的5-脂氧合酶，其主要焦点将是 对产生的代谢物进行立体化学分析， 纯化足以测试其生物活性的量; 2)花生四烯酸竞争的系统动力学分析 (and其代谢物）和DHGLA（及其代谢物）作为底物， 白三烯合成的关键酶，在这种情况下，5-脂氧合酶，LTA 水解酶和LTC合酶; 3）确定生物相关性 DHGLA衍生的代谢产物使用一系列生理和免疫 已知由以下脂氧合酶产物调节的测定： 花生四烯酸，和4）阐明之间的相互关系 胞嘧啶和类花生酸介导的免疫机制。 我们的远程 目的是确定观察到的效应的体内相关性， 体外实验

Arachidonic acid is the major fatty acid precursor for the synthesis of biologically active eicosanoids. The critical role of the eicosanoids as regulators of physiologic and immune mechanisms is well documented and, therefore, control of their levels is of great interest in the treatment of prophylaxis of many diseases. One of the promising strategies in this context is the modulation of eicosanoid production by providing alternate substrates for oxidative metabolism through dietary manipulations. Recently attention has been focused on the metabolism of dihomo-gamma- linolenic acid (DHGLA) because it is thought to be the agent responsible for the apparent effectiveness of primrose oil in the treatment of a variety of diseases. These include inflammatory processes, skin diseases, immunological disorders, premenstrual pain, and malignancy. The overall objective of the proposed research is to understand the basic mechanisms underlying the beneficial nutritional effects of DHGLA. The research is based on the premise that substitution of membrane arachidonic acid by DHGLA results in an attenuation of arachidonic acid-derived eicosanoid levels. The overall hypothesis to be tested is that DHGLA acts as a competitive inhibitor of oxidative enzymes with respect to arachidonic acid substrate, that the oxidation products of DHGLA are biologically less potent than arachidonic acid metabolites, and that in some cases the former compounds act as antagonists to the cellular receptors of eicosanoids. The central goal of the proposed project will be to produce and characterize the metabolites derived from DHGLA via the 5-lipoxygenase pathway and to test the relative bioactivities of these molecules in assays of immune and physiologic functions which are known to be regulated by the lipoxygenase products of arachidonic acid. The hypothesis will be addressed by a number of in vitro experiments, the specific aims of which are as follows: 1) synthesis and characterization of primary and secondary oxygenation products of DHGLA catalyzed by electrophoretically pure 5-lipoxygenase, the main focus of which will be on stereochemical analysis of the metabolites produced as well as purification of quantities sufficient to test their biological activities; 2) systematic kinetic analysis of the competition between arachidonic acid (and its metabolites) and DHGLA (and its metabolites) as substrates for key enzymes of leukotriene synthesis, in this case 5-lipoxygenase, LTA hydrolase, and LTC synthase; 3) determination of the biological relevance of DHGLA-derived metabolites using a battery of physiological and immune assays which are known to be regulated by the lipoxygenase products of arachidonic acid, and 4) elucidation of the interrelationship between cytosine and eicosanoid-mediated immune mechanisms. Our long-range objective is to determine the in vivo relevance of the effects observed in the in vitro experimentation.