Sheth A U, Knight T F, Pace E, Senekjian H O, Weinman E J
Am J Physiol. 1981 May;240(5):F395-9. doi: 10.1152/ajprenal.1981.240.5.F395.
Clearance and micropuncture studies were performed in Sprague-Dawley and Munich-Wistar rats to examine the nephron sites of chloride reabsorption in animals undergoing sustained volume expansion (SVE) (10% of body wt) with isotonic saline and in animals in which the extracellular fluid volume was expanded to 10% of body wt over 60 min, after which the sustaining saline volume was abruptly discontinued (recovery) (R). Net sodium and chloride balances were not significantly different in R compared with SVE. The fractional excretion of chloride, however, was significantly lower (2.62 +/- 0.25 vs. 4.18 +/- 0.62%, P less than 0.05). In the Sprague-Dawley rats, chloride delivery to the early distal tubule average 18% in both groups. Chloride delivery to the late distal tubule was significantly lower in R (4.39 +/- 0.79%) than in SVE (8.55 +/- 0.76%, P less than 0.005). In the Munich-Wistar rats, samples were obtained from the late distal tubule and base and tip of the papilla. Chloride delivery to the base did not differ from that to the late distal tubule in either group, but was significantly lower in R compared with SVE. These results indicate that the so-called "post-volume expansion" antinatriuresis is the result, at least in part, of enhanced reabsorption in the distal tubule.
在斯普拉格-道利大鼠和慕尼黑-威斯塔大鼠中进行了清除率和微穿刺研究，以检查在接受等渗盐水持续容量扩张（SVE）（体重的10%）的动物以及在60分钟内将细胞外液容量扩张至体重的10%、之后突然停止维持盐水输注（恢复）（R）的动物中，氯离子重吸收的肾单位部位。与SVE相比，R组的钠和氯净平衡无显著差异。然而，氯离子的分数排泄显著降低（2.62±0.25%对4.18±0.62%，P<0.05）。在斯普拉格-道利大鼠中，两组早期远端小管的氯离子输送平均为18%。R组晚期远端小管的氯离子输送（4.39±0.79%）显著低于SVE组（8.55±0.76%，P<0.005）。在慕尼黑-威斯塔大鼠中，从晚期远端小管以及乳头的基部和尖端获取样本。两组中，乳头基部的氯离子输送与晚期远端小管的无差异，但与SVE相比，R组显著降低。这些结果表明，所谓的“容量扩张后”钠潴留至少部分是远端小管重吸收增强的结果。
