Tucker B J, Mundy C A, Blantz R C
Am J Physiol. 1986 Jan;250(1 Pt 2):F169-75. doi: 10.1152/ajprenal.1986.250.1.F169.
Many studies in the literature have drawn conclusions regarding the mechanism of change in absolute proximal tubular reabsorption (APR) based on steady-state measurements of proximal reabsorptive rates and the peritubular capillary. The proximal reabsorptive rate, APR, is the product of the effective reabsorptive pressure (ERP) and the peritubular capillary reabsorptive coefficient (LpAR) (APR = ERP . LpAR). The ERP is defined by the net hydrostatic and oncotic pressure gradient acting across the capillary wall from interstitium to peritubular capillary flow. The relationship APR = ERP . LpAR is predefined, and steady-state measurements do not permit determination of causality because primary changes in any variable obligate a proportional change in a second variable. As an example of the difficulties in interpretation of this type of analysis, we have examined the APR and factors contributing to ERP and LpAR before and after the administration of benzolamide, a carbonic anhydrase inhibitor, to saline-expanded Munich-Wistar rats. Alterations in peritubular capillary fluid uptake cannot always be interpreted as casual mechanisms for changes in absolute fluid reabsorption but may result from primary alterations in epithelial transport.
文献中的许多研究基于近端重吸收率和肾小管周围毛细血管的稳态测量，得出了关于绝对近端肾小管重吸收（APR）变化机制的结论。近端重吸收率（APR）是有效重吸收压力（ERP）与肾小管周围毛细血管重吸收系数（LpAR）的乘积（APR = ERP·LpAR）。ERP由作用于从间质到肾小管周围毛细血管血流的毛细血管壁的净静水压和胶体渗透压梯度定义。APR = ERP·LpAR的关系是预先定义的，稳态测量不允许确定因果关系，因为任何变量的主要变化必然导致第二个变量成比例变化。作为这类分析解释困难的一个例子，我们在给生理盐水扩容的慕尼黑-威斯塔大鼠注射碳酸酐酶抑制剂苯唑酰胺前后，研究了APR以及影响ERP和LpAR的因素。肾小管周围毛细血管液体摄取的改变并不总是可以解释为绝对液体重吸收变化的因果机制，而可能是上皮转运的原发性改变所致。
