AGING ON EFFLUX AND TURNOVER OF HEPATIC GLUTATHIONE

肝脏谷胱甘肽流出和周转的老化

• 批准号: 3118593
• 负责人: MURAD OOKHTENS
• 金额: $ 10.98万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-05-01 至 1993-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3118593
• 关键词: aging; cysteine; glutathione; high performance liquid chromatography; hydrolysis; laboratory rat; liver metabolism; methionine; protein metabolism; radionuclides; scintillation counter; sulfur aminoacid; toxin metabolism

Glutathione (GSH) is a ubiquitous and vital tripeptide in mammalian organisms. It plays a critical role in detoxification of xenobiotics, electrophiles, peroxides and oxygen radicals. About 5% of cellular oxidative metabolism produces radical forms of oxygen. It has been proposed that the cumulative, irreversible damange by this process to cellular structure/function could be a key mechanism of aging. since GSH is the major intracellular defense agent against this process, its homeostasis and regulation in the aging organism is of utmost importance. The key role of the liver is hepatic and extrahepatic GSH metabolism makes it the organ of prime importance in GSH metabolism. The overall purpose of this proposal is to delineate the characteristics and mechanisms of changes in turnover and efflux of hepatic GSH as a function of age. In particular the following specific aims will be pursued: (1) Identification of changes inthe kinetics of hepatic sinusoidal and canalicular GSH efflux as a function of age. We will define whether the observed decline in the carrier-mediated sinusoidal efflux with age is due to changes in Vmax; Km, or both. We will also accurately define the changes in the kinetics of biliary efflux with age, by blocking biliary hydrolysis of GSH using AT-125. (2) Determination of the mechanisms of changes in the heptatic GSH turnover with age. Using improved designs and methods, the turnover rate of hepatic GSH turnover rate of hepatic GSH and its relationship to sinusoidal and biliary efflux will be measured by tracer-kinetic methods and multicompartmental analysis. (3) Delineation of the effect of perturbation of hepatic GSH pool size on turnover and efflux. These studies will probe in more depth the relationships and quantitative contribution of sinusoidal and canalicular efflux to the total hepatic turnover and provide more rigorous testing of the homogeneity of the hepatic GSH pool. (4) Determination of the role of availability of sulfur amino acids. These studies will explore the age-related correlates of hepatic uptake of methionine and cysteine. (5) Development of kinetic, compartmental model of hepatic GSH turnover and efflux in aging. The results of our experiments will be analyzed by multicompartmental methods with the aim of integrating the findings into a comprehensive model of GSH turnover and efflux in aging.

谷胱甘肽（GSH）是一种广泛存在的三肽类化合物，在脑血管疾病中起着重要的作用。 哺乳动物有机体。 它在解毒中起着关键作用 异生素、亲电子试剂、过氧化物和氧自由基。 关于 5%的细胞氧化代谢产生的自由基形式的 氧气 有人建议，累积的、不可逆转的 这一过程对细胞结构/功能的损害可能是 衰老的关键机制。 因为GSH是细胞内 抗此过程的防御剂、其体内平衡和调节 是至关重要的。 的关键作用 肝是肝，肝外GSH代谢使其 谷胱甘肽代谢中最重要的器官。 整体 本建议书的目的是描述 肝内GSH转换和外排的变化机制 年龄的函数。 具体而言，将 目的：（1）确定肝动脉血流动力学的变化 肝窦和小管GSH流出作为年龄的函数。 我们 将定义观察到的载体介导的 随着年龄的增加，窦状流出是由于Vmax、Km或两者的变化。 我们还将准确地定义 通过阻断胆汁中GSH的水解作用 AT-125号 (2)确定的变化机制 随着年龄增长，GSH呈七态转换。 使用改进的设计和 方法：采用酶联免疫吸附试验（ELISA）、酶联免疫吸附试验（ELISA）、酶联免疫吸附试验（ELISA）、酶联免疫吸附试验（ELISA）、酶联免疫吸附试验 肝内谷胱甘肽与肝窦及胆汁外排关系 将通过示踪剂动力学方法测量，并 多室分析。 (3)效力的界定 肝GSH池大小对转换和外排的干扰。 这些研究将更深入地探讨 窦状和小管流出量对 总肝转换率，并提供更严格的检测 肝GSH池的均一性。 (4)测定 含硫氨基酸的可利用性的作用。 这些研究将 探讨肝脏摄取与年龄相关的 甲硫氨酸和半胱氨酸。 (5)发展动力学、 肝GSH周转和外排房室模型 衰老 我们的实验结果将通过 多室方法，旨在整合 研究结果纳入GSH周转和外排的综合模型 在衰老。