20-HETE IN NO-MEDIATED REGULATION OF RENAL FUNCTION

描述(改编自申请者摘要)：一氧化氮(NO)和 细胞色素P450(CYP450)介导的二十烷类化合物 20-羟基二十碳四烯酸(20-HETE)是 综合身体功能的数量，包括维持血管张力 和肾功能；因此，它们与高血压的发生有关 高血压。因为NO的生理作用归因于 铁的氧化，一氧化氮从而调节血红素蛋白的活性，如 细胞色素P450酶系统。因此，NO系统是一种内生的 细胞色素P450二十烷类化合物产生的调控途径。NO还调节 其他体液因子的产生/活动，特别是内皮素(ET) 多肽。一氧化氮合酶(NOS)被抑制后，随后的肾脏 血流动力学改变，主要是由于NO的戒断 因此，可能反映了血管收缩因子CYP450的表达增强 二十碳二烯酸，尤其是20-HETE和/或ET多肽。基于：1)减少 NO供体硝普钠诱导HETES的肾微粒体合成 NW-硝基-L-精氨酸甲酯对小鼠肾脏反应的减弱作用 (L-NAME)，一氧化氮合酶抑制剂，由12，12二溴十二碳烯酸，和 20-HETE合成抑制剂和ETA受体拮抗剂BMS182874； 3)ET-1诱导肾脏释放20-HETE，我们推测NO 抑制内源性20-HETE的产生，可能与ET有关 生产，是维持机体内环境平衡的重要机制 血管张力和肾功能。我们进一步提出20-HETE是一种 NO活动的反调节器。这项提案的具体目标， 因此，主要有：1)确定NO对细胞色素P450依赖性的影响 花生四烯酸代谢及其对肾脏细胞色素P4A基因表达的影响 和蛋白质；2)确定20-HETE对肾脏的贡献 L-NAME引起的血流动力学和排泄反应；3)测定 如果20-HETE参与L-NAME的反应与ET多肽有关。 将在孵育的肾微体中评估AA到20-HETE的转化 与NO供体，以及L-精氨酸或 L-名字。将测定大鼠尿中20-HETE和ET-1的含量 用同样的药剂治疗。油气田减产的机理 通过测定细胞色素P4A mRNA的表达来评价NO对20-HETE的作用 和蛋白质。将进行急性肾清除研究，以确定 20-HETE在肾功能反应中的作用 L的行政管理-姓名。20-HETE在动态关系中的作用 一氧化氮合酶抑制后的血管和肾小管效应之间的关系 在慢性研究中进行检查，在这些研究中，高血压将被 L-名字。正如我们展示的刺激20-HETE产生的ET-1一样， 在L的名字治疗后显示出增加，我们将确定是否 20-HETE的产量也显示出在L之后有所增加 治疗后，他们将确定20-HETE产物是否与ET偶联 产生/激活ET受体，如果是，哪些受体是 牵涉其中。这些研究应该会增强我们对相互作用的了解。 NO，20-HETE和ET-1之间；内源性肾功能调节因子和 全身血流动力学，从而帮助我们理解 以NO产生不足为特征的条件的病理生理学。

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.