CELLULAR INTERACTIONS OF LEAD, CALCIUM, AND IRON

铅和基本元素之间的复杂相互作用，主要是 钙，铁，锌铜，并已在临床和 实验研究 的作用机制和毒理学意义 这些相互作用没有被清楚地理解。 我们的目标是扩大 我们之前通过在整个实验室进行一系列实验的发现 动物，细胞和亚细胞水平，以评估铅的影响 中毒对细胞内稳态和钙的基本功能的影响 和铁. 这些实验将共同检验以下一般假设： 铅的毒性是通过扰乱细胞内稳态来表达的 和基本要素的功能。 这项建议的具体目标是 收件人： 体内1.评价铅中毒对血铅浓度的影响 在肾脏，大脑， 大鼠主动脉、回肠和肝脏。 体外（钙）2.比较Pb和Ca的亚细胞定位， 确定铅诱导钙积累的亚细胞部位 在培养的肝细胞中。 3. 确定203 Pb进入电池的路线，并将 被动扩散的作用和相对重要性，液相 内吞作用和载体介导的转运（钙门）， Pb2+进入细胞。 4.评价铅对细胞内游离[Ca2+] 在微粒体、线粒体和透化大鼠肝细胞中。 5.评估铅中毒对钙调素和钙离子的影响， 介导的细胞功能位于选定的亚细胞钙结构域， 培养大鼠肝细胞。 体外（铁）6.建立稳态细胞动力学模型 培养肝细胞中59 Fe的稳态。 7.评估铅中毒对细胞内稳态的影响， 培养的大鼠肝细胞中的59 Fe。 8.将铅诱导的铁稳态变化与 铁介导培养大鼠细胞功能与血红素生物合成 肝细胞

Complex interactions between lead and essential elements, primarily calcium, iron, zinc copper, and have been reported in clinical and experimental studies. The mechanisms and toxicological significance of these interactions are not clearly understood. Out objective is to extend our previous finding by conducting a series of experiments at the whole animal, cellular, and subcellular level to evaluate the effects of lead intoxication on the cellular homeostasis and essential functions of calcium and iron. Together these experiments will test the general hypothesis that lead toxicity is expressed via a perturbation of the cellular homeostasis and function of essential elements. The specific aims of this proposal are to: In Vivo 1. evaluate the effect of lead intoxication on the concentration of essential elements in selected microscopic regions of kidney, brain, aorta, ileum, and liver of rats. In Vitro (Calcium) 2. compare the subcellular localization of Pb and Ca and to determine the subcellular site(s) of lead-induced calcium accumulation in cultured hepatocytes. 3. determine the route(s) by which 203Pb enters cells and to compare the roles and relative importance of passive diffusion, fluid-phase endocytosis, and carrier-mediated transport (calcium gates) in the entry of Pb2+ into cells. 4. evaluate the effect of lead on the regulation of cytosolic free [Ca2+] in microsomes, mitochondria, and permeabilized rat hepatocytes. 5. evaluate the effect of lead intoxication on calmodulin- and calcium- mediated cell functions located in selected subcellular calcium-domains of cultures rat hepatocytes. In Vitro (Iron) 6. develop a kinetic model for the steady-state cellular homeostasis of 59Fe in cultured hepatocytes. 7. evaluate the effect of lead intoxication on the cellular homeostasis of 59Fe in cultured rat hepatocytes. 8. correlate the lead induced changes in iron homeostasis with iron-mediated cell function and heme biosynthesis in cultured rat hepatocytes.