ROLE OF CA IN THE REGULATION OF ENERGY METABOLISM

该项目旨在评估 Ca 2+离子在能量代谢调节中的作用。 具体来说，我们有 将分离的心肌细胞暴露于各种预期 改变胞浆游离钙浓度（[Ca 2 +]c），并测量了 丙酮酸脱氢酶（PDH-A）的活性形式的量， 以及通过使用荧光螯合剂来估计[Ca 2 +]。 用于增加[Ca 2 +]c的方案包括血浆去极化 膜与氯化钾，取消钠+c电化学梯度与 哇巴因和短杆菌肽，抑制肌浆网钙摄取 咖啡因和使用代谢抑制剂来消耗细胞ATP。 我们 已经证明PDH-A的价值会随着这些因素的变化而增加 干预措施，以及Ca 2+运输到 线粒体介导这些增加。 此外，我们还采取了 荧光螯合剂技术的优势，以表征 KCl诱导的去极化导致[Ca 2 +]c增加的机制，以及 对β-肾上腺素能激动剂和佛波醇 酯盐酸盐的褪 我们还启动了一项分离肝细胞的研究， 研究[Ca 2 +]c值增加在介导 2-酮戊二酸脱氢酶和丙酮酸的活性增加 脱氢酶，其响应于激素胰高血糖素而发生， 加压素

This project is designed to assess the physiological importance of Ca2+-ions in the regulation of energy metabolism. Specifically, we have exposed isolated cardiac myocytes to a variety of conditions expected to alter cytosolic free Ca2+ concentration ([Ca2+]c), and have measured the amount of the active form of pyruvate dehydrogenase (PDH-A) which results, as well as estimating [Ca2+] by use of fluorescent chelating agents. Protocols used to increase [Ca2+]c include depolarization of the plasma membrane with KCl, abolition of the Na+c electrochemical gradient with ouabain and gramicidin, inhibition of sarcoplasmic reticulum Ca2+ uptake by caffeine and the use of metabolic inhibitors to deplete cellular ATP. We have demonstrated an increased value of PDH-A in response to each of these interventions, and an important role of Ca2+ transport into the mitochondria in mediating these increases. Further, we have taken advantage of the fluorescent chelating agent technology to characterize the mechanism of the increase in [Ca2+]c due to KCl-induced depolarization, and have established a sensitivity to beta -adrenergic agonists and to phorbol esters. We have also initiated a study of isolated hepatocytes, in order to investigate the importance of increased values of [Ca2+]c in mediating the increased activity of 2-oxoglutarate dehydrogenase and pyruvate dehydrogenase which occurs in response to the hormones glucagon and vasopressin.