Glomerular filtration dynamics in the dog during elevated plasma colloid osmotic pressure.
Glomerular filtration dynamics in the dog during elevated plasma colloid osmotic pressure.
复制标题
血浆胶体渗透压升高期间狗的肾小球滤过动态。
DOI：
10.1038/ki.1979.65
复制
发表时间：
1979
影响因子：
19.6
通讯作者：
L. Navar
中科院分区：
文献类型：
--
作者：
C. Thomas;P. Bell;L. Navar
为了确定犬的肾小球滤过系数（Kf）是否受血浆胶体渗透压（COP）变化的影响，我们对给予浓缩白蛋白溶液的犬进行了显微穿刺实验。在一组（N = 9）中，在输注450 - 600 ml 25%牛白蛋白溶液后评价滤过动力学。为了使急性容量扩张的影响最小化，我们还在实验前一天通过白蛋白负荷在另一组（N = 7）中实现了高COP水平。在所有实验中，将肾动脉压降至约90 mm Hg，以尽量减少可能导致高估单个肾单位滤过率（SNGFR）和肾小球压力（GP）的潜在误差。在急性扩张犬中，COP升高至23.0 +/-（SEM）0.9 mm Hg，SNGFR为59 +/- 6 nl/min，估计GP为61.0 +/- 2.0 mm Hg，近端小管压（PTP）为23.0 +/- 1.6 mm Hg，浅表滤过分数（SFF）为0.13 +/- 0.02。还观察到类似的全肾滤过分数降低，几乎完全是由于肾血流量显著增加。与未输注的对照犬（N = 13）相比，COP升高的犬的Kf显著更高，为5.3 +/- 0.6 nl/min/mm Hg，相比之下为3.4 +/- 0.3 nl/min/mm Hg。平均有效滤过压（EFP）为12 ± 1 mm Hg，肾小球毛细血管输出端的EFP为8.9 ± 1.2 mm Hg。在前一天输注的组中，COP为20.0 +/- 0.8 mmHg，SFF为0.26 +/- 0.01，SNGFR为70 +/-8 nl/min，GP为59 +/- 2 mmHg，PTP为19.0 +/- 1.5 mmHg。平均EFP为15 +/- 1 mm Hg，毛细血管输出端的EFP为7.5 +/- 0.7 mm Hg。kf为4.85 +/- 0.66 nl/min/mm Hg，该值显著高于COP为15.0 +/- 0.6 mm Hg的对照犬中获得的值。此外，一组用等渗白蛋白溶液扩张的对照犬（N = 4），尽管血浆体积扩张的程度与用浓缩白蛋白溶液扩张的组相似，但Kf并未表现出显着变化。这些实验与先前在大鼠中获得的发现一致，即Kf受COP的影响，尽管Kf的变化似乎小于大鼠中的变化。数据表明，即使在COP升高的这些条件下，犬的过滤过程的特征在于整个肾小球毛细血管长度的正过滤压力。
To determine if the glomerular filtration coefficient (Kf) of the dog is influenced by changes in plasma colloid osmotic pressure (COP), we conducted micropuncture experiments in dogs given concentrated albumin solutions. In one group (N = 9), filtration dynamics were evaluated following infusion of 450 to 600 ml of a 25% bovine albumin solution. To minimize the effects of acute volume expansion, we also achieved high COP levels in another group (N = 7) by albumin loading on the day prior to the experiment. In all experiments, renal arterial pressure was reduced to approximately 90 mm Hg to minimize potential errors that might lead to overestimation of single nephron filtration rate (SNGFR) and glomerular pressure (GP). In the acutely expanded dogs, COP increased to 23.0 +/- (SEM) 0.9 mm Hg, SNGFR was 59 +/- 6 nl/min, estimated GP was 61.0 +/- 2.0 mm Hg, proximal tubule pressure (PTP) was 23.0 +/- 1.6 mm Hg, and superficial filtration fraction (SFF) was 0.13 +/- 0.02. A similarly reduced whole kidney filtration fraction was also observed, due almost entirely to a marked increase in renal blood flow. When compared to noninfused control dogs (N = 13), Kf was significantly higher in the dogs with elevated COP, being 5.3 +/- 0.6 nl/min/mm Hg as compared to 3.4 +/- 0.3 nl/min/mm Hg. Average effective filtration pressure (EFP) was 12 +/- 1mm Hg, and EFP at the efferent end of the glomerular capillaries was 8.9 +/- 1.2 mm Hg. In the group infused on the prior day, COP was 20.0 +/- 0.8 mm Hg, SFF was 0.26 +/- 0.01, SNGFR was 70 +/-8 nl/min, GP was 59 +/- 2 mm Hg, and PTP was 19.0 +/- 1.5 mm Hg. Average EFP was 15 +/- 1 mm Hg, and EFP at the efferent end of the capillaries was 7.5 +/- 0.7 mm Hg. kf was 4.85 +/- 0.66 nl/min/mm Hg, a value significantly higher than that obtained in control dogs having a COP of 15.0 +/- 0.6 mm Hg. Furthermore, one group of control dogs (N = 4), expanded with an isooncotic albumin solution, did not exhibit significant changes in Kf even though the degree of plasma volume expansion was similar to the group expanded with concentrated albumin solution. These experiments are consistent with previous findings obtained in the rat that Kf is influenced by the COP, although the changes in Kf appear to be less than they are in the rat. The data indicate that even under these conditions of elevated COP, the filtration process in the dog is characterized by positive filtration pressures throughout the length of the glomerular capillaries.