DYNAMICS OF GLOMERULAR ULTRAFILTRATION IN RAT .4. DETERMINATION OF ULTRAFILTRATION COEFFICIENT
DYNAMICS OF GLOMERULAR ULTRAFILTRATION IN RAT .4. DETERMINATION OF ULTRAFILTRATION COEFFICIENT
复制标题
DOI：
10.1172/jci107324
复制
发表时间：
1973-01-01
影响因子：
15.9
通讯作者：
BRENNER, BM
中科院分区：
文献类型：
--
作者：
DEEN, WM;TROY, JL;BRENNER, BM
在特意设计的条件下，在突变 Wistar 大鼠的可及表面肾小球中测量压力和流速，以防止实现滤过压力平衡，即肾小球传出端的跨毛细血管静水压和胶体渗透压的均衡，如通常在正常缺水大鼠中观察到的那样。当大鼠血浆体积等于体重的 5% 时，血浆体积急剧膨胀导致肾小球血浆流量 (GPF) 水平升高，从而导致不平衡。在高 GPF 下测量的肾小球静水压和胶体渗透压用于计算超滤系数 Kf，即有效水渗透率和表面积的乘积。然后降低 GPF（通过主动脉收缩）或升高（通过颈动脉闭塞）以检查 Kfon GPF 的依赖性。发现Kfper肾小球的值0.08nl/(s·mmHg)在GPF的大约两倍范围内没有变化。这一发现与该实验室之前研究的数据相结合，使我们得出结论，肾小球滤过率 (GFR) 的血浆流量依赖性主要是由流量引起的平均超滤压变化引起的，而不是 Kf 的大幅变化。
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,Kf, 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 ofKfon GPF. The value ofKfper 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 inKf.