ROLE OF EICOSANOIDS IN RENIN RELEASE AND RENAL FUNCTION

氢过氧二十碳四烯酸（HPETE），或由 HPETE减少，可能影响肾血管阻力（RVR）， 通过对效应细胞的直接作用释放肾素（RR）， 通过包括抑制PGI 2合成酶的间接作用。 目的 这项建议的目的是确定哪些HPETE是由肾 脂氧合酶活性并阐明各种HPETE（15-、12-）的作用 和5-HPETE）对RVR和RR的影响， 离体灌注肾、离体肾小球和肾小球细胞 (JGC)在组织培养中。 初步工作将针对 肾组织的浓度和时间依赖性的表征 HPETE的效果和与相应的羟基酸的比较。 在 分析肾组织的花生四烯酸（AA）代谢模式， 该项目将严重依赖HPLC和GC-MS分析进行分离， 参与调节的特异性脂氧合酶产物的鉴定 RVR和RR。 将放射性标记输注至离体肾脏的HPETE 因此，功能变化可以被解释为 静脉中出现的放射性产物分布的变化 和尿液。 AA代谢的放射性转化研究将在 结合RR研究，使用灌注系统进行 使用富含小动脉附着的孤立肾小球。 这些 放射性转化研究将包括量化的程度， PGI 2转化为活性代谢物6-酮PGE 1。 通过比较 AA代谢谱与肾小球缺乏AA代谢的结果相比， 小动脉附件，以及完整和 去内皮化的肾动脉节段和培养的JGC， 可能重建哪些介质的RR是目前在 JGC的微环境 还将使用分离的灌流肾小球 评估RR可能通过倒数控制的假设 PGI 2和HPETE之间的相互作用。 将开展平行研究 用各种体外模型来确定甘露醇的影响， HPETE反应中的其他自由基清除剂。 在后期阶段， 项目，将研究类花生酸依赖性RR，因为它与 盐依赖型高血压的发病机制。 灌注肾 来自盐敏感和耐盐Dahl大鼠的肾小球将 检查对HPETE敏感性的可能菌株差异， 对RR和RVR的影响。 氧清除剂的影响 激进分子将被测试，作为评估假设的一部分， 高血压中的“低功能”RR机制是由于 清除自由基的细胞保护机制。

Hydroperoxy eicosatetraenoic acids (HPETEs), or oxygen radicals formed by reduction of HPETEs, may influence renal vascular resistance (RVR) and renin release (RR) through direct actions on the effector cells as well as through indirect effects involving inhibition of PGI2 synthetase. The aim of this proposal is to determine which HPETEs are formed by renal lipoxygenase activity and to clarify the role of various HPETEs (15-, 12- and 5-HPETE) on RVR and RR using several in vitro systems including isolated perfused kidneys, isolated glomeruli and juxtaglomerular cells (JGC) in tissue culture. Initial efforts will be directed towards characterization of the concentration and time-dependence of the renal effects of HPETE and comparison with corresponding hydroxy acids. In analyzing the pattern of arachidonic acid (AA) metabolism by renal tissue, the project will rely heavily on HPLC and GC-MS analyses for separation and identification of specific lipoxygenase products involved in modulation of RVR and RR. The HPETEs infused into isolated kidneys will be radiolabeled so that functional changes can be interpreted in terms of simultaneous variations in the profile of radioactive products appearing in the venous and urinary effluents. Radioconversion studies of AA metabolism will be undertaken, in conjunction with studies of RR, using a superfusion system employing isolated glomeruli enriched in arteriolar attachments. These radioconversion studies will include quantification of the extent of conversion of PGI2 to an active metabolite, 6-keto PGE1. By comparing the profile of AA metabolism to results obtained with glomeruli devoid of arteriolar attachments, as well as to the pattern in intact and de-endothelialized renal arterial segments and cultured JGC, it will be possible to reconstruct which mediators of RR are present in the microenvironment of JGC. Isolated superfused glomeruli will also be used to evaluate the hypothesis that RR may be controlled via a reciprocal interaction between PGI2 and HPETEs. Parallel studies will be carried out with the various in vitro models to determine the influence of mannitol and other free radical scavengers on HPETE responses. In later stages of the project, eicosanoid-dependent RR will be studied as it relates to the pathogenesis of a salt-dependent form of hypertension. Perfused kidneys and glomeruli from salt-sensitive and salt-resistant Dahl rats will be examined for possible strain differences in sensitivity to HPETEs as regards effects on RR and RVR. The influence of scavengers of oxygen radicals will be tested as part of efforts to evaluate the hypothesis that the "hypo-functional" RR mechanism in hypertension results from a deficit of cellular protective mechanisms for scavenging free radicals.