Schurek H J, Alt J M
Am J Physiol. 1981 Jun;240(6):F569-76. doi: 10.1152/ajprenal.1981.240.6.F569.
The effect of different albumin concentrations on whole kidney function has been studied in the isolated perfused rat kidney. When a dialyzer was included in the perfusion circuit, GFR and sodium transport remained nearly constant for 2 h. Perfusion flow rate was directly correlated with albumin concentration. GFR was low (0.56 ml.min-1.g-1) at high albumin concentration (7.6 g/100 ml) and highest (1.38 ml.min-1.g-1) when albumin was omitted. The latter observation differed from earlier findings by other investigators who found a reduced GFR in the absence of albumin. This reduced GFR could be explained by ureteral backpressure, which results from the use of narrow ureter catheters. Fractional sodium reabsorption was approximately 50% irrespective of load when albumin was absent, and reached 90% at a GFR of 0.95 ml.min-1.g-1 when 5-6 g/100 ml albumin was used. At reduced load, fractional sodium reabsorption approached in vivo values of 98%. Potassium secretion was observed at high urinary flow rates when albumin concentration was low; low urinary flow rates at high protein concentration were associated with net potassium reabsorption.
在离体灌注大鼠肾脏中研究了不同白蛋白浓度对全肾功能的影响。当在灌注回路中加入透析器时，肾小球滤过率（GFR）和钠转运在2小时内几乎保持恒定。灌注流速与白蛋白浓度直接相关。在高白蛋白浓度（7.6 g/100 ml）时GFR较低（0.56 ml·min⁻¹·g⁻¹），而在省略白蛋白时GFR最高（1.38 ml·min⁻¹·g⁻¹）。后一观察结果与其他研究者的早期发现不同，他们发现在无白蛋白时GFR降低。这种GFR降低可由输尿管反压来解释，输尿管反压是使用狭窄输尿管导管所致。当无白蛋白时，无论负荷如何，钠重吸收分数约为50%，当使用5 - 6 g/100 ml白蛋白时，在GFR为0.95 ml·min⁻¹·g⁻¹时钠重吸收分数达到90%。在低负荷时钠重吸收分数接近体内的98%。当白蛋白浓度低时，在高尿流率下观察到钾分泌；高蛋白浓度下的低尿流率与钾的净重吸收有关。
