20-HETE IN NO-MEDIATED REGULATION OF RENAL FUNCTION

20-HETE 对肾功能的无中介调节

• 批准号: 6357613
• 负责人: Adebayo O. Oyekan
• 金额: $ 5万
• 依托单位: TEXAS SOUTHERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2002-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6357613
• 关键词: arginine; cytochrome P450; eicosanoid metabolism; eicosanoids; endothelin; enzyme inhibitors; gel electrophoresis; gene expression; high performance liquid chromatography; hormone receptor; kidney circulation; kidney function; laboratory rat; messenger RNA; nitric oxide; nitric oxide synthase; renal tubular transport

DESCRIPTION (Adapted from the Applicant's Abstract): Nitric oxide (NO) and cytochrome P450 (CYP450)-mediated eicosanoids, especially 20-hydroxyeicosatetraenoic acid (20-HETE) are important determinants of a number of integrated body functions, including maintenance of vascular tone and renal function; hence, they are implicated in the genesis of hypertension. As the physiological actions of NO are attributable to the oxidation of iron, NO thereby modulates the activity of hemoproteins like the CYP450 enzyme system. The NO system is, therefore, an endogenous regulatory pathway for CYP450 eicosanoid production. NO also modulates the production/activity of other humoral factors, notably, endothelin (ET) peptides. Following inhibition of NO synthase (NOS), the ensuing renal hemodynamic changes which have been mainly attributable to withdrawal of NO may, therefore, reflect enhanced expression of vasoconstrictor CYP450 eicosanoids, especially 20-HETE and/or ET peptides. Based on: 1) reduced renal microsomal synthesis of HETEs by nitroprusside, an NO donor; 2) attenuation of the renal responses to Nw-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, by 12,12 dibromododec enoic acid (DBDD), an inhibitor of 20-HETE synthesis, and BMS182874, an ETA receptor antagonist; and 3) ET-1-induced renal release of 20-HETE, we hypothesize that NO inhibition of endogenous 20-HETE production, possibly linked to ET production, is an important homeostatic mechanism for maintenance of vascular tone and renal function. We further propose that 20-HETE is a counterregulator of NO activity. The Specific Aims of this proposal, therefore, are: 1) to determine the effect of NO on CYP450-dependent arachidonic acid (AA) metabolism and on the renal expression of CYP4A mRNA and protein; 2) to establish the contribution of 20-HETE to the renal hemodynamic and excretory responses induced by L-NAME; and 3) to determine if the involvement of 20-HETE in L-NAME response is linked to ET peptides. Conversion of AA to 20-HETE will be evaluated in renal microsomes incubated with NOdonors, and in microsomes from rats treated with L-arginine or L-NAME. Urinary production of 20-HETE and ET-1 will be determined in rats treated with the same agents. The mechanism of the reduced production of 20-HETE by NO will be evaluated by determining the expression of CYP4A mRNA and protein. Acute renal clearance studies will be performed to establish the contribution of 20-HETE in the renal functional response to administration of L-NAME. The role of 20-HETE in the dynamic relationship between vascular and tubular effects following NOS inhibition will also be examined in chronic studies in which hypertension will be induced with L-NAME. As ET-1, which we showed to stimulate 20-HETE production has also been shown to increase following L-NAME treatment, we will determine if 20-HETE production has also been shown to increase following L-NAME treatment, they will determine if 20-HETE production is coupled to ET production/activation of ET receptors and, if so, which receptors are involved. These studies should enhance our knowledge of the interplay between NO, 20-HETE and ET-1; endogenous regulators of renal function and systemic hemodynamics, and thus help our understanding of the pathophysiology of conditions characterized by inadequate production of NO.

描述（改编自申请人的摘要）：一氧化氮（NO）和 细胞色素P450（CYP 450）介导的类花生酸，尤其是 20-羟基二十碳四烯酸（20-HETE）是 许多综合身体功能，包括维持血管张力 和肾功能;因此，它们与 高血压 由于NO的生理作用可归因于 铁的氧化，NO从而调节血红素蛋白的活性， CYP 450酶系统 因此，NO系统是内源性的。 CYP 450类花生酸产生的调节途径。 NO还调节 其他体液因子的产生/活性，特别是内皮素（ET） 缩氨酸 抑制NO合酶（NOS）后， 血流动力学变化主要归因于NO的排出 因此，可能反映了血管收缩剂CYP 450的表达增强 类花生酸，尤其是20-HETE和/或ET肽。 基于：1）减少 一氧化氮供体硝普钠引起的HETE肾微粒体合成; 2） 对N-硝基-L-精氨酸甲酯的肾反应的衰减 （L-NAME），一氧化氮合酶抑制剂，由12，12二溴十二碳烯酸（DBDD）， 20-HETE合成抑制剂和BMS 182874，ETA受体拮抗剂; 3）ET-1诱导肾组织释放20-HETE，我们推测NO 抑制内源性20-HETE产生，可能与ET有关 生产，是一个重要的稳态机制，维持 血管张力和肾功能。 我们进一步提出，20-HETE是一种 NO活性的反调节剂。 本提案的具体目标， 因此，主要是：1）确定NO对CYP 450依赖性 花生四烯酸（AA）代谢和对肾脏CYP 4A mRNA表达的影响 2）确定20-HETE对肾脏的贡献， L-NAME诱导的血液动力学和排泄反应;以及3）确定 如果20-HETE参与L-NAME反应与ET肽有关。 将在孵育的肾微粒体中评价AA向20-HETE的转化 与NO供体，以及在用L-精氨酸或 L-NAME。 将在大鼠中测定20-HETE和ET-1的尿产生 用同样的药剂治疗。 本文还探讨了玉米秸秆减产的机理 20-将通过测定CYP 4A mRNA的表达来评价NO的HETE 和蛋白质。 将进行急性肾清除率研究，以确定 20-HETE在肾功能反应中的作用 给予L-NAME。 20-HETE在动态关系中的作用 在NOS抑制后的血管和肾小管效应之间的关系也将是 在慢性研究中检查，其中高血压将被诱导， L-NAME。 作为ET-1，我们发现刺激20-HETE的产生也 在L-NAME治疗后增加，我们将确定是否 20-HETE的产量也显示出增加以下L-NAME 治疗时，他们将确定20-HETE的产生是否与ET结合， ET受体的产生/激活，如果是，哪些受体是 涉案 这些研究应该能增进我们对 NO、20-HETE和ET-1之间的关系;肾功能的内源性调节剂， 全身血流动力学，从而帮助我们了解 病理生理学的条件，其特征在于不充分的生产NO。