Effect of formate on volume reabsorption in the rabbit proximal tubule.
Effect of formate on volume reabsorption in the rabbit proximal tubule.
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甲酸盐对兔近曲小管容量重吸收的影响。
DOI：
10.1172/jci112803
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Aronson,PS
中科院分区：
文献类型：
--
作者：
Schild,L;Giebisch,G;Karniski,LP;Aronson,PS
对兔肾皮质微绒毛膜的研究表明，氯的吸收可能是通过氯/甲酸盐交换和甲酸的非离子扩散循环进行的。我们测试了这种转运机制是否参与了兔近端小管对活性氯化钠的重吸收。在近端小管S2段灌流低浓度HCO-3溶液时，腔内加入甲酸盐(0.25-0.5 mm)和浴液使体积重吸收(JV)增加60%，跨上皮电位差保持不变。甲酸盐对JV的作用是完全可逆的，并可被哇巴因和鲁米那4，4‘-二异硫氰基二苯乙烯-2，2’-二磺酸所抑制。甲酸盐(0.5 mM)不能刺激高HCO-3溶液灌流的早期近曲小管的JV。根据微型玻璃pH微电极的测量，甲酸盐对JV的影响的缺乏与使用高HCO-3溶液作为灌流液时小管液的酸化程度较小有关。这些数据表明，氯/甲酸盐的交换和甲酸的非离子扩散循环是近端小管中活跃的、电子中和的氯化钠重吸收的机制。
Studies on microvillus membrane from rabbit kidney cortex suggest that chloride absorption may occur by chloride/formate exchange with recycling of formic acid by nonionic diffusion. We tested whether this transport mechanism participates in active NaCl reabsorption in the rabbit proximal tubule. In proximal tubule S2 segments perfused with low HCO-3 solutions, the addition of formate (0.25-0.5 mM) to the lumen and the bath increased volume reabsorption (JV) by 60%; the transepithelial potential difference remained unchanged. The effect of formate on JV was completely reversible and was inhibited both by ouabain and by luminal 4,4'-diisothiocyanostilbene-2,2'-disulfonate. Formate (0.5 mM) failed to stimulate JV in early proximal convoluted tubules perfused with high HCO-3 solutions. As measured by miniature glass pH microelectrodes, this lack of formate effect on JV was related to a less extensive acidification of the tubule fluid when high HCO-3 solutions were used as perfusate. These data suggest that chloride/formate exchange with recycling of formic acid by nonionic diffusion represents a mechanism for active, electroneutral NaCl reabsorption in the proximal tubule.