CELLULAR INTERACTIONS OF LEAD, CALCIUM, AND IRON

铅和必需元素之间的复杂相互作用，主要是 钙，铁，锌，铜，已被报道在临床和 实验研究。其作用机制及毒理学意义 这些相互作用还没有被清楚地理解。我们的目标是延伸 我们之前的发现是通过在整个 动物、细胞和亚细胞水平评估铅的影响 钙中毒对细胞内稳态和基本功能的影响 还有铁。这些实验将共同检验这样一个普遍假设： 铅中毒是通过扰乱细胞内环境平衡表现出来的。 和基本要素的作用。这项提议的具体目的是 致： 在活体实验中，评估铅中毒对血药浓度的影响。 在选定的肾脏、大脑、 大鼠的主动脉、回肠和肝脏。 在体外(钙)2.比较铅和钙的亚细胞定位和 确定铅致钙蓄积的亚细胞部位(S) 在培养的肝细胞中。 3、确定203Pb进入细胞的路径(S)，比较 被动扩散在流体中的作用和相对重要性 内吞作用和载体介导的转运(钙门)进入 Pb2+进入细胞 4.评价铅对细胞内游离钙的调节作用 在微粒体、线粒体和通透性大鼠肝细胞中。 5.评估铅中毒对钙调蛋白和钙离子的影响 介导性细胞功能定位于特定的亚细胞钙结构域 培养大鼠肝细胞。 体外(铁)6.建立稳态细胞的动力学模型 ~(59)Fe在培养肝细胞中的动态平衡。 7.评价铅中毒对大鼠细胞内环境平衡的影响 ~(59)Fe在培养大鼠肝细胞中的表达。 8.铅引起的铁稳态变化与 铁介导的细胞功能和培养大鼠的血红素生物合成 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.