ROLE OF CA IN THE REGULATION OF ENERGY METABOLISM

这个项目是为了评估生理意义的 钙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在各种条件下，预计 改变细胞内游离钙浓度([Ca~(2+)]_c)，并测定 产生的丙酮酸脱氢酶(PDH-A)活性形式的量， 以及通过使用荧光螯合剂来估计[Ca2+]。 用于提高[Ca~(2+)]c的方案包括血浆去极化 用KCl膜，取消了Na+c的电化学梯度 哇巴因和格拉西丁对肌浆网钙摄取的抑制作用 咖啡因和代谢抑制剂的使用来耗尽细胞的ATP。我们 已经证明PDH-A的价值增加，以响应其中的每一个 干预，以及钙离子转运到细胞内的重要作用 线粒体在调节这些增加中起作用。此外，我们已经采取了 荧光络合剂技术在表征有机污染物中的优势 KCl2诱导的去极化引起[Ca~(2+)]_c升高的机制 已经建立了对β-肾上腺素能激动剂和佛波醇的敏感性 酯类化合物。我们还启动了一项对分离的肝细胞的研究，以便 探讨细胞内[Ca~(2+)]_c升高在细胞调节中的重要性 2-氧戊二酸脱氢酶和丙酮酸活性的提高 一种脱氢酶，是对激素胰高血糖素和 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.