Wen S F, Stoll R W
Am J Physiol. 1979 Jun;236(6):F567-74. doi: 10.1152/ajprenal.1979.236.6.F567.
Proximal and distal tubule micropuncture studies were performed in normal and uremic remnant-kidney dogs to examine the tubule mechanism of glucose reabsorption before and after 10% extracellular volume expansion. In normal dogs volume expansion markedly inhibited glucose reabsorption in the proximal convoluted tubule, but the ensuing increase in further distal glucose delivery was nearly completely reabsorbed in the intermediate segment (between late proximal tubule and distal tubule). In the uremic, remnant-kidney dogs, glomerulotubular balance for glucose was well maintained in the proximal convoluted tubule despite an adaptive increase in nephron filtration rate. Volume expansion markedly increased glucose delivery out of the proximal convoluted tubule and an incomplete glucose reabsorption in the intermediate segment led to glycosuria. When glucose delivery to the intermediate segment was increased to a comparable degree by subthreshold glucose loading in hydropenic normal dogs, glucose reabsorption in this segment was virtually complete, suggesting that in the volume-expanded uremic dogs glucose reabsorptive capacity in the intermediate segment was reduced. Thus, the intermediate segment appears to play a significant role in the fine regulation of urinary glucose excretion.
在正常和尿毒症残余肾犬中进行近端和远端肾小管微穿刺研究，以检查细胞外液量扩张10%前后葡萄糖重吸收的肾小管机制。在正常犬中，容量扩张显著抑制近端曲管中的葡萄糖重吸收，但随后向更远端的葡萄糖输送增加量几乎在中间段（近端小管晚期和远端小管之间）被完全重吸收。在尿毒症残余肾犬中，尽管单个肾单位滤过率适应性增加，但近端曲管中葡萄糖的球管平衡仍保持良好。容量扩张显著增加了近端曲管的葡萄糖输出量，中间段不完全的葡萄糖重吸收导致糖尿。当通过限水正常犬的阈下葡萄糖负荷使输送到中间段的葡萄糖量增加到可比程度时，该段的葡萄糖重吸收实际上是完全的，这表明在容量扩张的尿毒症犬中，中间段的葡萄糖重吸收能力降低。因此，中间段似乎在尿葡萄糖排泄的精细调节中起重要作用。
