Foulkes E C
Pflugers Arch. 1975 Oct 16;360(1):1-6. doi: 10.1007/BF00584321.
Measurement in the rat of renal artery-to-vein transit times permitted evaluation of movement of 14C-labelled urate and of other solutes out of the peritubular inulin spaces in the renal cortex. No interaction between urate and PAH could be demonstrated at this level. Provided the peritubular disappearance may be equated to cellular uptake a mean unidirectional urate flux across peritubular membranes equal to about 1/3 of total renal load may be calculated. This value greatly exceeds the net secretory flux of urate. Such a fact can be explained by the likelihood of significant post-proximal reabsorption of secreted urate, and/or by the conclusion that peritubular urate permeability exceeds that of the luminal side. Assignment of the limiting step in urate secretion to the luminal cell membranes, in contrast to a determining role played by peritubular membranes in PAH transport, can account for the lack of interaction between PAH and urate at the peritubular membrane in rats.
在大鼠中测量肾动脉至静脉的转运时间，有助于评估14C标记的尿酸盐及其他溶质从肾皮质肾小管周围菊粉间隙的运出情况。在此水平上，未发现尿酸盐与对氨基马尿酸（PAH）之间存在相互作用。假设肾小管周围溶质的消失等同于细胞摄取，那么可以计算出尿酸盐跨肾小管周围膜的平均单向通量约为肾脏总负荷的1/3。该值大大超过尿酸盐的净分泌通量。这一事实可以通过分泌的尿酸盐在近端小管后段存在显著重吸收的可能性，和/或肾小管周围尿酸盐通透性超过管腔侧通透性的结论来解释。与PAH转运中肾小管周围膜起决定性作用相反，将尿酸盐分泌的限速步骤归因于管腔细胞膜，可以解释大鼠肾小管周围膜处PAH与尿酸盐之间缺乏相互作用的现象。
