Carbonic anhydrase-dependent bicarbonate reabsorption in the rat proximal tubule.
Carbonic anhydrase-dependent bicarbonate reabsorption in the rat proximal tubule.
复制标题
大鼠近曲小管中碳酸酐酶依赖性碳酸氢盐重吸收。
DOI：
10.1152/ajprenal.1979.236.1.f58
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
F. Rector
中科院分区：
文献类型：
--
作者：
M. Lucci;D. Warnock;F. Rector
在大鼠近曲小管中碳酸氢盐重吸收依赖于碳酸酐酶的程度已通过体内微灌注和微量热法测量总CO2浓度进行了研究。以13 nl/min的超滤液样溶液灌注肾小管，并使用[14 C]菊粉测量体积重吸收率（JV）。在灌注液中加入800或100 μ M乙酰唑胺可完全抑制总CO2的重吸收。对照组总CO2重吸收率（JtCO 2）为147 +/- 23 pmol/mm.min，乙酰唑胺将JtCO 2降低至-3 +/- 5 pmol/mm. min。乙酰唑胺将JV从对照组的2.3 +/- 0.4 nl/mm. min降低至0.8 +/- 0.1 nl/mm. min，降幅为65%。乙酰唑胺的剂量-反应曲线显示抑制JtCO 2的I50为4 μ M。乙酰唑胺的非活性同系物叔丁基乙酰唑胺没有降低JV或抑制碳酸氢盐重吸收，表明乙酰唑胺对JtCO 2的影响是特异性的碳酸酐酶抑制。由于碳酸氢盐重吸收被碳酸酐酶抑制完全阻断，因此无需假设碳酸再循环或不依赖碳酸酐酶的碳酸氢盐重吸收。
The extent to which bicarbonate reabsorption in the rat proximal convoluted tubule depends on carbonic anhydrase has been examined by in vivo microperfusion and the measurement of total CO2 concentration by microcalorimetry. Tubules were perfused with an ultrafiltrate-like solution at 13 nl/min, and volume reabsorptive rate (JV) was measured using [14C]inulin. Addition of either 800 or 100 microM acetazolamide to the perfusion solution completely inhibited the reabsorption of total CO2. The control total CO2 reabsorptive rate (JtCO2) was 147 +/- 23 pmol/mm.min, and acetazolamide reduced JtCO2 to -3 +/- 5 pmol/mm.min. Acetazolamide reduced JV by 65% from a control of 2.3 +/- 0.4 to 0.8 +/- 0.1 nl/mm.min. The dose-response curve for acetazolamide showed that the I50 for inhibition of JtCO2 was 4 microM. The inactive congener of acetazolamide, t-butyl acetazolamide, did not reduce JV or inhibit bicarbonate reabsorption, indicating that the effect of acetazolamide on JtCO2 was specific for carbonic anhydrase inhibition. Since bicarbonate reabsorption was completely blocked by carbonic anhydrase inhibition, there is no need to postulate either carbonic acid recycling or carbonic anhydrase-independent bicarbonate reabsorption.