20-HETE IN NO-MEDIATED REGULATION OF RENAL FUNCTION

20-HETE 对肾功能的无中介调节

• 批准号: 6017309
• 负责人: Adebayo O. Oyekan
• 金额: $ 4.44万
• 依托单位: NEW YORK MEDICAL COLLEGE
• 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 1999-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6017309
• 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 (CYP450) 介导的类二十烷酸，尤其是 20-羟基二十碳四烯酸 (20-HETE) 是 身体综合功能的数量，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，例如 CYP450酶系统。 因此，NO 系统是一个内源性的系统。 CYP450 类二十烷酸生产的调控途径。 NO 还调节 其他体液因子的产生/活性，特别是内皮素 (ET) 肽。 抑制一氧化氮合酶（NOS）后，随之而来的肾 血流动力学变化主要归因于NO的撤除 因此，可能反映了血管收缩剂 CYP450 表达的增强 类二十烷酸，尤其是 20-HETE 和/或 ET 肽。 基于：1）减少 通过硝普钠（NO 供体）肾微粒体合成 HETE； 2） 肾脏对 Nw-硝基-L-精氨酸甲酯的反应减弱 (L-NAME)，一种 NOS 抑制剂，由 12,12 二溴十二烯酸 (DBDD) 产生， 20-HETE合成抑制剂，以及ETA受体拮抗剂BMS182874； 3) ET-1 诱导肾释放 20-HETE，我们假设 NO 抑制内源 20-HETE 产生，可能与 ET 有关 生产，是维持体内平衡的重要机制 血管张力和肾功能。 我们进一步提出 20-HETE 是 NO 活性的反调节剂。 该提案的具体目标， 因此，有： 1) 确定 NO 对 CYP450 依赖性的影响 花生四烯酸 (AA) 代谢及其对 CYP4A mRNA 肾表达的影响 和蛋白质； 2) 确定20-HETE对肾脏的贡献 L-NAME 诱导的血流动力学和排泄反应； 3) 确定 如果 L-NAME 反应中 20-HETE 的参与与 ET 肽有关。 将在孵育的肾微粒体中评估 AA 向 20-HETE 的转化 与 NO 供体以及用 L-精氨酸或 L-名称。 将测定大鼠尿液中 20-HETE 和 ET-1 的产生量 用同样的药剂处理。 减产机理 通过测定 CYP4A mRNA 的表达来评估 NO 的 20-HETE 和蛋白质。 将进行急性肾清除研究以确定 20-HETE 对肾功能反应的贡献 L-NAME 的管理。 20-HETE 在动态关系中的作用 NOS 抑制后血管和肾小管效应之间的关系也将 在慢性研究中进行了检查，其中高血压会诱发 L-名称。 作为 ET-1，我们证明它可以刺激 20-HETE 的产生 已显示 L-NAME 治疗后增加，我们将确定是否 L-NAME 后 20-HETE 产量也显示增加 治疗时，他们将确定 20-HETE 的生产是否与 ET 相结合 ET 受体的产生/激活，如果是的话，哪些受体是 涉及。 这些研究应该增强我们对相互作用的了解 NO、20-HETE 和 ET-1 之间；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 以 NO 产生不足为特征的病症的病理生理学。