PGE RECEPTOR - LIVER AND FAT METABOLISM

我们的总体目标是澄清前列腺素的调节作用 E系列对肝脏和脂肪细胞的代谢有影响。具体目标 是为了确定体内前列腺素E受体的下调是否 前列腺素E_2类似物对SD大鼠的治疗 胰岛素和胰升糖素受体的异源调节变化； 确定前列腺素E受体下调是否与 WE等脂肪细胞腺苷环化酶G/F亚单位的变化 最近在肝细胞中表现出；评估G/F的变化 子单元可用性与PGE中的变化具体相关 质膜上的受体密度或G/F亚单位是否发生变化 也与胰岛素和胰升糖素受体下调有关；以及 确定前列腺素E受体下调对某些疾病的影响 肝脏和脂肪细胞代谢的cAMP相关方面。这位将军 前列腺素E、胰岛素和前列腺素能受体下调的研究进展 胰高血糖素将使用常规技术来研究结合 这些受体的放射性标记配体。将导致下调监管 大鼠体内注射前列腺素E_2类似物、胰岛素和 分别为胰高血糖素。腺苷环化酶活性的研究将在 使用质膜进行剂量-反应曲线表征 控制和下调动物和刺激物，如前列腺素E、高血糖素、 氟化钠、GppNHp和Forsklin。腺苷酸G/F亚基 将通过使用霍乱毒素来更广泛地研究环化酶 用[~(32)P]NAD和SDS凝胶激活和标记G/F亚基。灯座 使用红细胞或Cyc细胞的亚基重建研究 将进行检查以确认下调调节的肝脏中亚单位的变化 和脂肪细胞。这项提议的一个主要方面是进行实验，以 确定前列腺素E是否对肝脏有生物学意义的改变 和通过与前列腺素E受体相互作用的脂肪代谢。这将是 通过对与以下物质相关的代谢过程的广泛研究来接近 脂肪和肝脏组织中的环磷酸腺苷。这将涉及到对 糖原分解、糖异生、脂肪酸合成、脂肪酸氧化、 还有脂肪分解。这个项目与健康相关的本质源于我们的 先前在人类中观察到前列腺素E可引起循环激素的变化 以及与葡萄糖动态平衡有关的底物。

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.