METAL SPECIATION--EFFECT ON TRANSPORT AND INTERACTIVE TOXICITY

一般认为，金属离子不能自由循环。 生物体液，但与内源性配体(例如，蛋白质， 氨基酸等)在血液和细胞中。金属离子可能是终极的 毒素，但剂量-反应关系和/或进入细胞的途径是 无疑是受血液或浴缸中金属的形态控制 5~6成熟。这个项目的目标是建立一种关系 金属迁移和金属毒性使用的化学物种 血。本课题的研究假设如下：一、在系统的 循环中，金属将主要以内源金属络合物的形式存在 而不是作为自由离子。II.金属摄取率和 体外系统的毒性程度取决于实际的金属 在血液中发现的物种。这个项目将集中在硫醇结合上 配体(半胱氨酸、谷胱甘肽、白蛋白、金属硫蛋白)，并将检查 金属络合物对细胞转运和毒性的影响。金属 将被研究的离子属于元素周期表的第IIB族： 镉(II)、汞(II)和锌(II)。具体目标包括：1)。 确定一组内部一致的金属配体的值 不同体腔中的形成常数、配基浓度 (包括血液、细胞外和细胞内液体)和总金属 在不同的身体隔间中发现的浓度。使用解决方案平衡 在标准计算机程序上找到的计算方法可以预测最多 在不同的身体中应该发现的普遍金属物种 车厢。2)。金属-蛋白质交换反应将使用 最近发展起来的层析技术。热力学，以及 交换反应的动力学可能由 作为时间函数的金属离子的洗脱和/或位置。3)。 用In检测金属离子络合物的吸收和毒性 培养中分离细胞群体的体外制备。单元格 种群将包括红细胞和红细胞幽灵；LLC-PK1 肾细胞和初级近端肾小管制剂；和ARL-18 (肝)上皮细胞和原代肝细胞制剂。

It is generally recognized that metal ions do not circulate freely in biological fluids, but are bound to endogenous ligands (e.g., proteins, amino acids, etc.) in blood and cells. The metal ion may be the ultimate toxin but the dose-response relationship and/or the access into the cell is undoubtedly controlled by the form of the metal in the blood or bathing medium. The goal of this project is to establish a relationship between metal transport and metal toxicity using the chemical species that occur in blood. The hypotheses of this project are as follows: I. In the systemic circulation, metals will exist primarily as metal complexes with endogenous ligands and not as the free ions. II. The rate of metal uptake and the extent of toxicity in in vitro systems is dependent on the actual metal species which are found in blood. This project will focus on thiol binding ligands (cysteine, glutathione, albumin, metallothionein) and will examine the effect of metal complexes on cellular transport and toxicity. Metal ions which will be examined belong to Group IIB of the Periodic Table: Cd(II), Hg(II), and Zn(II). The specific aims include the following: 1). Determine an internally consistent set of values for the metal-ligand formation constants, ligand concentrations in various body compartments (including blood, extra- and intracellular fluids), and total metal concentrations found in various body compartments. Use solution equilibria calculations found on standard computer programs to predict the most prevalent metal species that should be found in the various body compartments. 2). Metal-Protein exchange reactions will be studied using recently developed chromatographic techniques. The thermodynamics, and possibly the kinetics, of the exchange reaction can be determined by the elution and/or location of the metal ion as a function of time. 3). Examine the uptake and toxicity of the metal ion complexes by using in vitro preparations of isolated cell populations in culture. The cell populations will include erythrocytes and erythrocyte ghosts; LLC-PK1 kidney cells and primary proximal kidney tubule preparations; and ARL-18 (liver) epithelial cells and primary liver hepatocyte preparations.