TRANSPORT-TOXICITY OF INORGANIC MERCURY IN THE NEPHRON

汞仍然是一种严重的环境和职业危害， 从工业废料到牙科汞合金。肾脏是其中一个目标 汞的毒性作用，可能是因为肾脏的 汞，积累更多的无机汞比任何其他器官。的 肾脏也是汞排泄的主要途径， 对肾小管损伤的机制知之甚少， 无机汞的迁移、积累和毒性。因此非常 关于尿排泄中所涉及的机制知之甚少， 金属。这项拨款的主要目的是描述肾脏疾病的特点， 无机汞的迁移、积累、毒性和代谢。 这项赠款的目的将在体内和体外使用 技术.我们将使用的主要技术之一是孤立的 灌流兔肾小管。这项技术将使我们能够确定 同时，肾小管摄取和跨上皮腔-浴 以及汞在海洋各孤立部分的池-腔迁移 肾单位我们将研究汞的运输、积累和毒性 在近端小管（S1，S2和S3）的孤立节段中，髓质 Henle袢和皮质集合管的粗支。这些研究 将确定是否存在传输的轴向不均匀性， 汞沿着肾单位的积聚。关于远端的研究 段是重要的，因为很少有人知道的处理， 汞超过近端小管。由于无机汞 我们还将研究化合物对游离巯基的影响， 含有巯基的物质。为了确定 如果细胞外半胱氨酸、谷胱甘肽和白蛋白参与 汞在肾单位各段的积累和运输，我们将 使用放射性标记的无机汞（203 Hg）和放射性标记的 半胱氨酸和谷胱甘肽（35 S）和白蛋白（125 I）在体内和体内 体外汞和配体的肾内定位将是 在肾脏的运输和积累过程中， 的配体和汞将研究在隔离灌注段的 肾单位汞的积累和迁移也将 研究了当汞在兔血浆超滤液中时， 与金属硫蛋白复合。此外，运输、 汞的累积和毒性将在肾脏 细胞内谷胱甘肽被耗尽，当细胞内合成 金属硫蛋白被刺激。我们还将尝试将汞本地化， 汞中毒家兔肾组织亚细胞组分的变化 和各种配体。此外，自动记录技术将 与离体灌流管技术相结合， 测定细胞内汞的定位和累积。我们将 还确定金属螯合剂DMPS和DMSA是否促进去除 汞从各种孤立的灌注肾单位节段时，适用于 腔或基底外侧膜。总之，从这项研究中，我们应该 能够确定内吞作用和载体介导的 肾脏中游离和结合的转运和蓄积 无机汞此外，这项研究应该提供一些见解， 探讨汞对肾上皮细胞毒性的影响因素。

Mercury remains a serious environmental and occupational hazard, ranging from industrial waste to dental amalgams. The kidney is one of the target organs for the toxic effects of mercury, presumably because the kidney of mercury, accumulates more inorganic mercury than any other organ. The kidney also serves as a major route for the excretion of mercury, but very little is known about the mechanisms involved in the renal tubular transport, accumulation and toxicity of inorganic mercury. Thus very little is known about the mechanisms involved in the urinary excretion of the metal. The main thrust of this grant is to characterize the renal transport, accumulation, toxicity, and metabolism of inorganic mercury. The aims of this grant will be carried out using both in vivo and in vitro techniques. One of the principal techniques we will use is the isolated perfused rabbit renal tubule. This technique will allow us to determine simultaneously the renal tubular uptake and transepithelial lumen-to-bath and bath-to-lumen transport of mercury in various isolated segments of the nephron. We will study the transport, accumulation and toxicity of mercury in isolated segments of the proximal tubule (S1, S2, and S3), medullary thick limb of Henle's loop and cortical collecting ducts. These studies will determine if there is axial heterogeneity for transport and accumulation of mercury along the nephron. The studies on the distal segments are important because very little is known about the handling of mercury beyond the proximal tubule. Since inorganic mercury binds avidly to free sulfhydryl groups, we will also examine the effects of compounds that contain sulfhydryl groups on these processes. In order to determine if extracellular cysteine, glutathione and albumin participate in the accumulation and transport of mercury in segments of the nephron, we will use both radiolabelled inorganic mercury (203Hg) and radiolabelled cysteine and glutathione (35S) and albumin (125I) both in vivo and in vitro. The intrarenal localization of mercury and ligand will be determIned for zones of the kidney, while the transport and accumulation of the ligand and mercury will be studied in isolated perfused segments of the nephron. The accumulation and transport of mercury will also be studied when mercury is in an ultrafiltrate of rabbit plasma and when it is complexed with metallothionein. Furthermore, the transport, accumulation and toxicity of mercury will be evaluated when renal intracellular glutathione is depleted and when intracellular synthesis of metallothionein is stimulated. We will also attempt to localize mercury in subcellular fractions of renal tissue from rabbits treated with mercury and the various ligands. In addition, an autometallographic technique will be combined with the isolated perfused tubular technique in an attempt to determine the intracellular localization and accumulated mercury. We will also determine if the metal chelators DMPS and DMSA promote the removal of mercury from various isolated perfused nephron segments when applied to the luminal or basolateral membrane. In summary, from this study we should be able to determine the role of endocytosis and carrier mediated transport in the renal transport and accumulation of free and bound inorganic mercury. Furthermore, this study should provide some insights into the factors influencing the toxicity of mercury in renal epithelia.