Evaluation of bicarbonate transport in rat distal tubule: effects of acid-base status.
Evaluation of bicarbonate transport in rat distal tubule: effects of acid-base status.
复制标题
大鼠远曲小管中碳酸氢盐转运的评估：酸碱状态的影响。
DOI：
10.1152/ajprenal.1982.243.4.f335
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
DuBoseJr,TD
中科院分区：
文献类型：
--
作者：
Lucci,MS;Pucacco,LR;Carter,NW;DuBoseJr,TD
先前的微穿刺研究利用间接方法来估计大鼠浅表远端小管中碳酸氢盐的转运，表明远端碳酸氢盐重吸收过程通常远低于饱和水平。我们实验室最近的研究未能证明该部分存在自发的酸不平衡 pH，这意味着碳酸氢盐的重吸收率低于之前的估计。本实验的目的是 1) 在控制碳酸氢盐输送的同时测量大鼠浅表远端小管的绝对碳酸氢盐重吸收率，2) 检查酸碱状态的变化对碳酸氢盐重吸收率的影响。对五组处于不同酸碱平衡状态的大鼠进行了研究。在对照缺水组、合并呼吸性酸中毒-代谢性碱中毒组、急性呼吸性酸中毒组或急性代谢性酸中毒组中未检测到显着的碳酸氢盐重吸收。相反，持续 3 天的代谢性酸中毒导致碳酸氢盐重吸收率显着为 52.6 +/- 13.9 pmol。毫米-1。分钟-1。仅在持续 3 天的慢性代谢性酸中毒期间观察到远端小管中显着的碳酸氢盐重吸收，这与该通常低容量的部分对全身酸碱状态的慢性变化的适应是一致的。
Previous micropuncture studies utilizing indirect methods to estimate bicarbonate transport in the rat superficial distal tubule have indicated that the distal bicarbonate reabsorptive process normally operates well below the saturation level. Recent studies from our laboratory failed to demonstrate a spontaneous acid disequilibrium pH in this segment, implying that the bicarbonate reabsorptive rate was less than previously estimated. The purpose of the present experiments were 1) to measure the rate of absolute bicarbonate reabsorption by the rat superficial distal tubule while controlling bicarbonate delivery, and 2) to examine the effects of alterations in acid-base status on the rate of bicarbonate reabsorption. Five groups of rats in different states of acid-base balance were studied. No significant bicarbonate reabsorption was detected in the control hydropenic, combined respiratory acidosis-metabolic alkalosis, acute respiratory acidosis, or acute metabolic acidosis groups. In contrast, metabolic acidosis of 3 days duration resulted in a significant bicarbonate reabsorptive rate of 52.6 +/- 13.9 pmol . mm-1 . min-1. The observation of significant bicarbonate reabsorption in the distal tubule only during chronic metabolic acidosis of 3 days duration is compatible with adaptation of this normally low-capacity segment to chronic changes in systemic acid-base states.