PGE RECEPTOR - LIVER AND FAT METABOLISM

我们的总体目标是澄清调节作用， 对肝脏和脂肪细胞的代谢有影响。 具体目标 是为了确定是否下调PGE受体的体内 用PGE 2类似物治疗Sprague-Dawley大鼠伴随有 胰岛素和胰高血糖素受体的异源调节变化; 确定PGE受体的下调是否与 在脂肪细胞中腺苷酸环化酶G/F亚基的变化，如我们 最近在肝细胞中证实;为了评估G/F的变化是否 子单元可用性与前列腺素E的变化特别相关 质膜上的受体密度或G/F亚单位是否发生变化 也与胰岛素和胰高血糖素受体下调有关;和 为了确定PGE受体下调对某些 肝脏和脂肪细胞代谢的cAMP相关方面。 总 研究前列腺素E、胰岛素和前列腺素E受体下调的方法 胰高血糖素将使用常规技术研究结合 这些受体的放射性标记配体。 下调将被诱导 在Sprague-Dawley大鼠体内通过注射PGE 2类似物、胰岛素和 胰高血糖素。 腺苷酸环化酶活性的研究将是 使用来自 对照和下调的动物和刺激物如PGE，胰高血糖素， 氟化钠、GppNHp和毛喉素。 腺苷酸G/F亚基 环化酶将通过使用霍乱毒素得到更广泛的研究 用[32 P]NAD和SDS凝胶活化和标记G/F亚基。 G/F 使用红细胞或cyc细胞的亚单位重建研究 以确认下调肝脏中亚单位的变化 和脂肪细胞。 这项建议的一个主要方面涉及实验， 确定PGE是否在肝脏中产生有生物学意义的改变 通过与前列腺素E受体的相互作用来调节脂肪代谢。 这将 通过广泛的研究代谢过程， 脂肪和肝组织中的环腺苷酸。 这将涉及研究 糖原分解，脂肪生成，脂肪酸合成，脂肪酸氧化， 和脂解作用。 该项目的健康相关性质源于我们的 先前在人类中观察到PGE诱导循环激素的变化 和与葡萄糖稳态相关的底物。

Our overall goal is to clarify the regulatory effects that prostaglandins of the E series have on liver and fat cell metabolism. The specific aims are to ascertain whether down-regulation of PGE receptors by in vivo treatment of Sprague-Dawley rats with a PGE2-analog is accompanied by heterologous regulatory changes in receptors for insulin and glucagon; to determine whether down-regulation of the PGE receptor is associated with changes in the G/F subunit of adenylate cyclase in fat cells such as we have recently demonstrated in liver cells; to assess whether changes in G/F subunit availability are specifically associated with changes in PGE receptor density on plasma membranes or whether changes in the G/F subunit are also associated with insulin and glucagon receptor down-regulation;and to ascertain the consequences of PGE receptor down-regulation on certain cAMP-related aspects of liver and fat cell metabolism. The general approach to studying down-regulation of receptors for PGE, insulin and glucagon will be to use conventional techniques for studying the binding of radiolabeled ligands for these receptors. Down-regulation will be induced in vivo in Sprague-Dawley rats by injection of a PGE2-analog, insulin and glucagon, respectively. Studies of adenylate cyclase activity will be performed to characterize dose-response curves using plasma membranes from control and down-regulated animals and stimulators such as PGE, glucagon, sodium fluoride, GppNHp and forskolin. The G/F subunit of adenylate cyclase will be studied more extensively through the use of cholera toxin activation and labeling of the G/F subunit with [32P]NAD and SDS gels. G/F subunit reconstitution studies using either red blood cells or cyc- cells will be performed to confirm changes in the subunit in down-regulated liver and fat cells. A major aspect of this proposal involves experiments to ascertain whether PGE exerts biologically meaningful alterations in liver and fat metabolism through interactions with the PGE receptor. This will be approached through extensive studies of metabolic processes related to cyclic AMP in fat and liver tissues. This will involve studies of glycogenolysi, gluconeogenesis, fatty acid synthesis, fatty acid oxidation, and lipolysis. The health-related nature of this project emanates from our prior observation in humans that PGE induces change in circulating hormones and substrates related to glucose homeostasis.