Dynamics of glomerular ultrafiltration in the rat. IV. Determination of the ultrafiltration coefficient.
Dynamics of glomerular ultrafiltration in the rat. IV. Determination of the ultrafiltration coefficient.
复制标题
大鼠肾小球超滤的动力学。
DOI：
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发表时间：
1973
影响因子：
15.9
通讯作者：
B. Brenner
中科院分区：
文献类型：
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作者：
W. Deen;J. L. Troy;C. Robertson;B. Brenner
在旨在防止达到过滤压力平衡的条件下，对突变Wistar大鼠可接近的表面肾小球的压力和流速进行了测量，即正常缺水大鼠肾小球传出端的跨毛细血管静水压力和球囊压力的均衡。当大鼠血浆体积等于体重的5%时，由于血浆体积的急剧扩大而引起的肾小球血浆流量(GPF)水平升高时，出现不平衡。用高GPF下测得的肾小球静水压力和球囊压力计算超滤系数K(F)，即有效水力通透性与表面积的乘积。然后将GPF降低(通过主动脉缩窄)或升高(通过颈动脉阻断)，以检查K(F)对GPF的依赖性。每个肾小球的K(F)值，0.08nL/(s.mm Hg)，在GPF的大约两倍范围内没有变化。这一发现与本实验室以前的研究数据相结合，使我们得出结论：血浆流量对肾小球滤过率(GFR)的依赖主要是由于平均超滤压力的流量诱导变化，而不是K(F)的巨大变化。
Pressures and flow rates were measured in accessible surface glomeruli of mutant Wistar rats under conditions deliberately designed to prevent achievement of filtration pressure equilibrium, that is, the equalization of transcapillary hydrostatic and oncotic pressures by the efferent end of the glomerulus as typically observed in the normal hydropenic rat. Disequilibrium was obtained at elevated levels of glomerular plasma flow (GPF) brought about by acute expansion of plasma volume with a volume of rat plasma equal to 5% of body weight. Glomerular hydrostatic and oncotic pressures measured at high GPF were used to calculate the ultrafiltration coefficient, K(f), the product of effective hydraulic permeability and surface area. GPF was then either lowered (by aortic constriction) or raised (by carotid occlusion) in order to examine the dependence of K(f) on GPF. The value of K(f) per glomerulus, 0.08 nl/(s.mm Hg), was found not to vary over an approximately twofold range of GPF. This finding, taken together with data from previous studies from this laboratory, leads us to conclude that plasma-flow dependence of glomerular filtration rate (GFR) results primarily from flow-induced changes in mean ultrafiltration pressure, rather than large changes in K(f).