Nitric Oxide Regulation of Adrenal Steroidogenesis

描述（由申请人提供）：血管内皮细胞（EC）释放a 生物活性介质（PGI 2、一氧化氮（NO）和 内皮素），其作用于邻近的平滑肌细胞以影响血管 语气在肾上腺皮质，随着肾上腺动脉变小并分成 毛细血管和窦状隙，平滑肌层丢失， EC的一侧与类固醇生成细胞在解剖学上紧密接触。 因此，在肾上腺皮质的毛细血管中，这些介质可能影响 邻近类固醇生成细胞的功能。我们把研究重点放在 内皮源性NO对类固醇生成的作用。我们发现， 供体抑制血管紧张素II（All）刺激的醛固酮释放。的 NO的抑制作用不是由环GMP介导的，而是由NO结合到 参与醛固酮生物合成的细胞色素P450酶。我们无法 检测ZG细胞NO合成、NOS活性及NOS蛋白表达。 然而，肾上腺毛细血管内皮细胞含有NOS并释放NO。 假设EC在解剖学上与ZG细胞非常接近， 肾上腺皮质，释放NO和调节或调节醛固酮释放。的 拟议的研究将调查外源性、内源性和 内皮源性NO对醛固酮释放的影响。这些研究将在 在体外培养的牛ZG细胞和肾上腺毛细血管内皮细胞中。此外，研究 将在灌注的大鼠肾上腺和体内麻醉的 大鼠该假设将通过解决四个具体目标进行测试：（1）我们 将表征外源性NO对培养的细胞中醛固酮释放的影响， 牛ZG细胞将测试NO供体- 醛固酮在改变氧浓度的条件下释放。 进一步的研究将确定NO抑制的生物合成步骤， 慢性一氧化氮治疗对醛固酮生成和类固醇生成影响 内切酶(2)由于ZG细胞没有NOS，我们将确定 内源性NO通过转导细胞赋予ZG细胞NOS活性 一氧化氮合酶的腺病毒(3)我们将描述的影响， 内皮源性NO对ZG细胞释放醛固酮的影响。使用共孵育 内皮细胞和ZG细胞，我们将确定激动剂对NO释放的影响 以及NO对ZG细胞释放醛固酮的作用。(4)我们将 确定内皮NO在调节类固醇生成和肾上腺皮质激素分泌中的作用 血流在原位灌注肾上腺和在体内在麻醉 大鼠

DESCRIPTION (provided by applicant): Vascular endothelial cells (ECs) release a number of biologically-active mediators (PGI2, nitric oxide (NO) and endothelin) that act on adjacent smooth muscle cells to influence vascular tone. In the adrenal cortex, as adrenal arteries get smaller and divide into capillaries and sinusoids, the smooth muscle layer is lost and the abluminal side of the EC comes in close anatomical contact with the steroidogenic cells. Thus, in the capillaries of the adrenal cortex, these mediators may influence the function of the adjacent steroidogenic cells. We have focused our studies on the role of endothelial-derived NO on steroidogenesis. We found that the NO donors inhibit angiotensin II (All)-stimulated aldosterone release. The inhibition by NO is not mediated by cyclic GMP but by NO binding to the cytochrome P450 enzymes involved in aldosterone biosynthesis. We were unable to detect NO synthesis, NO synthase (NOS) activity or NOS protein in ZG cells. However, adrenal capillary ECs contain NOS and release NO. We wilt test the hypothesis that ECs, which are in close anatomical proximity to ZG cells in the adrenal cortex, release NO and regulate or modulate aldosterone release. The proposed studies will investigate the effects of exogenous, endogenous and endothelial-derived NO on aldosterone release. These studies will be conducted in vitro in cultured bovine ZG cells and adrenal capillary ECs. Also, studies will be performed in the perfused rat adrenal gland and in vivo in anesthetized rats. The hypothesis will be tested by addressing four specific aims: (1) We will characterize the effect of exogenous NO on aldosterone release in cultured bovine ZG cells. The effect of the NO donor, deta-nonoate, will be tested on aldosterone release under conditions that vary the oxygen concentration. Additional studies will determine the biosynthetic step inhibited by NO and the effect of chronic NO treatment on aldosterone production and steroidogenic enzymes. (2) Since ZG cells do not have NOS, we will determine the effect of endogenous NO by conferring NOS activity on ZG cells by transducing the cells with an adenovirus containing NOS. (3) We will characterize the influence of endothelial-derived NO on ZG cell aldosterone release. Using co-incubation of ECs and ZG cells, we will determine the effect of agonists on the release of NO from ECs and the action of this NO on ZG cell aldosterone release. (4) We will determine the role of endothelial NO in regulating steroidogenesis and adrenal blood flow in the in situ perfused adrenal gland and in vivo in anesthetized rats.