CORTICOSTEROID METABOLISM IN JUVENILE HYPERTENSION

本项目的目标是阐明结构，性质， 11 β-羟基类固醇脱氢酶的生物化学功能， 由11 β-脱氢酶和11-氧化还原酶组成的酶系统 件. 该系统在皮质类固醇代谢中起关键作用。 我们预计，该计划的成功完成将 深入了解11 β-羟基类固醇脱氢酶 复杂参与血压调节，如何干扰 其功能与一种形式青少年高血压（AME）有关， 如何通过皮质类固醇代谢的催化作用， 以及组织生长和成熟。 我们将使用抗体来对抗 均质11 β-脱氢酶（11 β DH）组分产生于 兔和11 β DH的药理学抑制剂，如 大黄酸，以测试酶“保护” I型受体对盐皮质激素活性11 β- 通过将11 β-羟基类固醇氧化为 无活性的11-氧代形式。 将在体外进行研究，以便 探索抑制的分子基础，并在体内， 建立AME动物模型。 我们已经确定11 β DH是一种 糖蛋白 我们将研究它的糖苷结构， 碳水化合物组分对酶功能的重要性。 我们将 使用我们已经产生的单特异性多克隆抗体， 同源11 β DH筛选大鼠肝脏cDNA表达文库 整合到噬菌体载体中。 我们的目标是确定 来源于结构基因的mRNA的核苷酸序列， 由此推导出11 β DH的一级氨基酸序列。 我们将 从人胎盘中分离酶，并与 克隆衍生的多肽和鼠源的酶。 的 在我们的实验中产生的抗体和cDNA将用作 组织化学探针定量11 β DH的分布 抗原及其相关的mRNA在细胞和组织内，并监测 酶水平的变化对激素干预的反应。 我们计划 以纯化皮质类固醇11-氧化还原酶，该酶催化 将可的松还原为皮质醇，并与11 β DH合作 维持类固醇体内平衡 纯化后， 将进行与11 β DH计划类似的分析研究， 执行。 这些调查将帮助我们了解a）如何 11 β DH活性的缺乏导致高血压; B） 控制氧化和还原的生理机制 皮质类固醇C-11

The goals of this project are to elucidate the structure, properties, and biochemical functions of 11 beta-hydroxysteroid dehydrogenase, an enzyme system composed of 11 beta-dehydrogenase and 11-oxoreductase components. This system plays a key role in corticosteroid metabolism. We anticipate that successful accomplishment of this program will provide insight into how the 11 beta-hydroxysteroid dehydrogenase complex participates in blood pressure regulation, how disturbances in its function are related to a form of juvenile hypertension (AME), and how, through catalysis of corticosteroid metabolism, it mediates cell and tissue growth and maturation. We will use antibodies against the homogeneous 11 beta-dehydrogenase (11 beta DH) component generated in rabbits and pharmacological inhibitors of 11 beta DH, such as glycyrrhetinic acid, to test the hypothesis that the enzyme "protects" type I receptors against the mineralocorticoid activity of 11 beta- hydroxycorticosteroids by oxidizing the 11 beta-hydroxysteroids to the inactive 11-oxo forms. Studies will be performed in vitro in order to explore the molecular basis for the inhibition, and in vivo in order to develop an animal model of AME. We have determined that 11 beta DH is a glycoprotein. We will examine its glycoside structure, and the significance of the carbohydrate component for enzyme function. We will use monospecific polyclonal antibodies we have generated with homogeneous 11 beta DH to screen rat liver cDNA expression libraries incorporated into bacteriophage vectors. Our goal is to determine the nucleotide sequence of the mRNA derived from the structural gene and to deduce from this the primary amino acid sequence of 11 beta DH. We will isolate enzyme from human placenta and compare its properties with the clonally derived polypeptide and the enzyme of murine origin. The antibodies and cDNAs generated in our experiments will be used as histochemical probes to quantitate the distribution of 11 beta DH antigen and its associated mRNA within cells and tissues, and to monitor changes in enzyme level in response to hormonal intervention. We plan to purify corticosteroid 11-oxoreductase, the enzyme that catalyzes the reduction of cortisone to cortisol, and which cooperates with 11 beta DH in maintaining steroid homeostasis. Subsequent to purification, analytical studies similar to those planned for 11 beta DH will be performed. These investigations will help us understand a) how deficiency of 11 beta DH activity leads to hypertension; b) the physiological mechanism that control oxidation and reduction of corticosteroid at C-11.