Renal Function in Vertebrates

小行星9513892 该项目涉及脊椎动物肾功能的比较研究。这些研究强调肾小管（肾脏的主要功能单位）运输的一般领域，特别是有机物质的运输，以及离子和水的排泄的调节。在这些广泛的领域内，研究将包括以下方面的继续研究：1）肾小管转运带负电荷的有机物质的机制和调节（有机阴离子），主要是对氨基马尿酸盐（PAH），荧光素和尿酸盐，以及带正电荷的有机物质2）调节细胞内pH（pHi），特别是当其涉及有机阴离子和阳离子的转运时;肾小管对滤过液的重吸收机制及其调控。这些研究集中在具有简单肾小管结构的爬行动物肾脏，以及具有从简单、表面类似爬行动物的肾小管到深、复杂的类似爬行动物的肾小管的鸟类肾脏。有机物质的肾小管运输在清除尿酸盐（鸟类和大多数爬行动物氮代谢的主要排泄终产物）和许多有毒外源物质以及调节重要内源物质的浓度方面起着特别重要的作用。在爬行动物和鸟类中，这些有机物质运输的细胞步骤和肾小管部位表现出相当大的变化，可能与肾小管的类型及其在运输其他有机物质、离子和水方面的功能有关。细胞内pH值的调节，这可能是相当不同的爬行动物和鸟类的肾小管，可能发挥重要作用，在确定这些有机物质的运输。肾小管对滤过液的净重吸收的调节对维持正常的体液平衡至关重要。它似乎显示了鸟类肾脏中不同小管群体的差异，这可能与过滤速率及其调节的差异有关。流体重吸收的耦合溶质重吸收可能显着不同的爬行动物和鸟类之间的肾小管和鸟类肾小管的人口，这种耦合可能涉及到过滤速率的变化，以及消除有机物质。这些研究的方法将主要涉及工作与隔离灌注和非灌注肾小管，并将利用定量光学技术以及同位素技术来评估运输率，细胞内运输步骤，和细胞内pH值。液体重吸收过程的评价将涉及直接定性和定量测量的液体被重吸收。结果应提供重要的信息的机制和调节肾小管运输的有机分子和液体的重吸收，以及这些过程如何涉及到爬行动物和鸟类肾脏的结构和其他功能差异。所获得的信息将有助于了解这些物种如何在恶劣的环境中生存，以及它们的肾脏如何帮助它们处理当前和潜在的环境毒素。 ***

9513892 Dantzler This project involves comparative studies of kidney function in vertebrates. The studies emphasize the general area of transport by the kidney tubules (the primary functioning units in the kidney), particularly of organic substances, and the regulation of excretion of ions and water. Within these broad areas, the investigations will involve continuations of studies on: 1) the mechanisms and regulation of kidney tubular transport of negatively charged organic substances (organic anions), primarily p-aminohippurate (PAH), fluorescein, and urate, and positively charged organic substances (organic cations), primarily tetraethylammonium (TEA); 2) the regulation of intracellular pH (pHi), especially as it relates to the transport of organic anions and cations; and 3) the mechanisms and regulation of the kidney tubular reabsorption of filtered fluid. These studies concentrate on reptilian kidneys, with their simple renal tubule structure, and on avian kidneys, with their kidney tubules ranging from simple, superficial reptilian-like ones to deep, complex mammalian-like ones. The kidney tubular transport of organic substances plays a particularly important role in eliminating urate (the major excretory end product of nitrogen metabolism in birds and most reptiles) and many toxic exogenous substances and in regulating the concentrations of important endogenous substances. The cellular steps in transport and the tubular sites of transport of these organic substances show considerable variation in reptiles and birds and may relate to the types of renal tubules and their function in the transport of other organic substances and ions and water. The regulation of intracellular pH, which may be quite different in reptilian and avian renal tubules, may play an important role in determining the transport of these organic substances. The regulation of net tubular reabsorption of filtered fluid is essential to maintaining normal fluid balance. It appears to show variations in the different t ubule populations in the avian kidney and this may relate to differences in filtration rate and its regulation. The coupling of fluid reabsorption to solute reabsorption may differ significantly between reptilian and avian kidney tubules and among populations of avian kidney tubules and this coupling may relate to changes in filtration rate as well as the elimination of organic substances. The approach to these studies will involve work primarily with isolated perfused and nonperfused renal tubules and will take advantage of quantitative optical techniques as well as isotopic techniques to evaluate rates of transport, intracellular transport steps, and intracellular pH. Evaluation of the process of fluid reabsorption will involve direct qualitative and quantitative measurements of the fluid being reabsorbed. The results should supply significant information on the mechanisms and regulation of kidney tubule transport of organic molecules and the reabsorption of fluid and how these processes relate to structural and other functional differences in reptilian and avian kidneys. The information obtained will help in understanding how these species survive in hostile environments and the ways in which their kidneys help them deal with current and potential environmental toxins. ***