REGULATION OF INDIVIDUAL NEPHRON FILTRATION RATES

我们的长期目标是增加对监管的理解 通过利用鸟类肾脏的独特结构，肾单位发挥作用 沙漠啮齿动物肾脏的高度专门化结构，以及 哺乳动物和鸟类肾的特殊运输特性。禽类 肾脏有类似于爬行动物肾脏的非常简单的 肾小球(单个毛细血管环)独立于每一个发挥作用， 不直接对集中机制作出贡献，并可以停止 在某些情况下完全过滤；类似于 在集中机制中共同发挥作用的哺乳动物肾单位， 通常不会停止过滤，但可能会改变其过滤速度；以及 动脉和门静脉的血液供应一种品系的鸡有 肾源性尿崩症。沙漠啮齿动物的肾脏 延髓旁肾单位比皮质浅层大好几倍 肾和一个很长的乳头。这种结构上的异质性 肾单位介于肾单位的结构异质性之间 在禽类肾脏和实验大鼠肾脏中。主要目标包括 研究：1)肾小球结构和功能，包括定量的 禽类肾脏的超微结构和滤过压； 骨髓功能和浓缩机制，包括氨基酸 哺乳动物延髓旁肾单位的转运，氨基酸在 哺乳动物延髓功能和注意力缺陷(S) 遗传性肾源性尿崩症。计算机辅助定量 过滤屏障及可利用面积的超微结构分析 用于过滤将用于检查简单的禽类小球。活体内 微穿刺压测量将有助于确定禽类肾小球 不同利尿剂状态下滤过动力学与结构的关系。 体内微穿刺法和体外连续微量输液法 微穿刺法和肾脏的微灌注法及氨基酸分析 切片提取物将用于进一步确定氨基酸的重吸收。 在Henle‘s圈尖的远端的延髓旁肾单位，循环 尿液中细胞渗透和容量调节的氨基酸 在实验室老鼠和沙漠啮齿动物中的浓度。体内清除量 离体血清白蛋白的测定及门静脉灌流和体外灌流 禽类采集管及其酶活性的测定 收集管将用于确定鸡的肾功能缺陷(S) 肾源性尿崩症。

The long-term objective is to increase understanding of the regulation of nephron function by exploiting the unique structure of avian kidneys, the highly specialized structure of kidneys of desert rodents, and the specialized transport properties of mammalian and avian nephrons. Avian kidneys have nephrons resembling reptilian nephrons with very simple glomeruli (single capillary loop) that function independently of each, do not contribute directly to the concentrating mechanism, and can cease filtering altogether under some circumstances; nephrons resembling mammalian nephrons that function together in the concentrating mechanism, do not normally cease filtering, but may alter their filtration rates; and both arterial and portal venous blood supplies One strain of chickens has nephrogenic diabetes insipidus. Kidneys of desert rodents have juxtamedullary nephrons several times larger than superficial cortical nephrons and a very long papilla. This structural heterogeneity of nephrons is intermediate between the structural heterogeneity of nephrons in avian kidneys and laboratory rat kidneys. The primary goals involve studies of: 1) glomerular structure and function, including quantitative ultrastructure and filtration will pressures in avian kidneys; and 2) medullary function and concentrating mechanism, including amino acid transport by juxtamedullary mammalian nephrons, the role of amino acids in mammalian medullary function, and concentrating defect(s) in birds with genetic nephrogenic diabetes inipidus. Computer-assisted quantitative ultrastructural analysis of the filtration barrier and the area available for filtration will be used to examine simple avian glomerulus. In vivo micropuncture pressure measurements will help define avian glomerular filtration dynamics in relation to structure in varying diuretic states. In vivo micropuncture and continuous microinfusion, in vitro microperfusion, and amino acid analyses of micropuncture samples and kidney slice extracts will be used to further define amino acid reabsorption distal to the tips of Henle's lops of juxtamedullary nephrons, recycling of amino acids for cellular osmotic and volume regulation during urine concentration in laboratory rats and desert rodents. In vivo clearance determinations and portal infusions and in vitro perfusions of isolated avian collecting ducts and determinations of enzyme activities in these collecting ducts will be used to define the renal defect(s) in chickens with nephrogenic diabetes insipidus.