CHARACTERIZATION OF HEPATIC ANGIOTENSIN II RECEPTORS

血管紧张素-血管紧张素系统在血压控制中是重要的， 但它在大多数高血压发病机制中的作用是 不确定 现有证据表明，血管对 血管紧张素II（AII）受生理刺激调节， 在某些高血压疾病中发生病理改变。 的目标 拟议的研究是表征AII与其 受体的免疫反应组织，并探讨其机制 影响细胞的敏感性 大鼠肝血浆AII受体 膜将使用放射性配体结合来鉴定和表征 技术. 这些受体与细胞过程的功能性偶联 将通过测量糖原磷酸化酶刺激来确定， 腺苷酸环化酶抑制在完整的，酶解离的 肝细胞 阳离子和鸟嘌呤核苷酸对受体的影响 数量和亲和力将被确定，以帮助定义生理控制 机制等 AII受体将从亲和标记的 膜和它们的物理化学性质由流体动力学确定 和电泳方法。 分子大小的激动剂特异性变化， 亚基组成和化学反应性将寻求确定 伴随受体活化的分子变化。 分离与 使用亲和层析纯化AII受体将是 尝试从亲和标记的和天然的膜。 如果成功， 将在家兔中产生抗受体抗体 微免疫技术。 这些方法将应用于动物 生理和病理生理改变的模型， 肾素-血管紧张素系统活性，以检验细胞 反应性由A11受体调节。 可能变动 受体表达（数量，亲和力）和活性（偶联至 生物化学事件）将与对以下的生理反应相关： 在这些动物身上尝试定义分子机制 涉案 在拟议的研究中开发的方法应 容易适用于血管、肾上腺、 腺体和其他肾素-血管紧张素系统的生理靶器官， 并且可以提供对高血压疾病的病理生理学的了解。

The reini-angiotensin system is important in the control of blood pressure, but its role in the pathogenesis of most forms of hypertension is uncertain. Existing evidence suggests that vascular responsiveness to angiotensin II (AII) is regulated by physiologic stimuli and perhaps may be pathologically altered in certain hypertensive disorders. The goal of the proposed research is to characterize the interaction between AII and its receptor in a hormonally-responsive tissue and to explore the mechanisms which influence cellular sensitivity. AII receptors in rat liver plasma membranes will be identified and characterized using radioligand binding techniques. Functional coupling of these receptors to cellular processes will be established by measuring glycogen phosphorylase stimulation and adenylate cyclase inhibition in intact, enzymatically-dissociated hepatocytes. The effects of cations and guanine nucleotides on receptor number and affinity will be determined to help define physiologic control mechanisms. AII receptors will be solubilized from affinity-labeled membranes and their physical-chemical properties determined by hydrodynamic and electrophoretic methods. Agonist-specific changes in molecular size, subunit composition and chemical reactivity will be sought to identify molecular changes attendant on receptor activation. Isolation and purification of AII receptors using affinity chromatography will be attempted from affinity-labeled and native membranes. If successful, anti-receptor antibodies will be generated in rabbits using micro-immunization techniques. These methods will be applied to animal models with physiologic and pathophysiologic alterations in renin-angiotensin system activity to test the hypothesis that cellular responsiveness is modulated by the A11 receptor. Possible changes in receptor expression (number, affinity) and activity (coupling to biochemical events) will be correlated with physiologic responsiveness to AII in these animals in an attempt to define molecular mechanisms involved. The methods developed during the proposed research should be readily applicable to the study of AII receptors in blood vessels, adrenal gland and other physiologic target organs of the renin-angiotensin system, and may provide insight into the pathophysiology of hypertensive disorders.