Chamberlin M E, Mandel L J
Am J Physiol. 1987 May;252(5 Pt 2):F838-43. doi: 10.1152/ajprenal.1987.252.5.F838.
Na+-K+-ATPase activity was measured in a suspension of rabbit medullary thick ascending limb tubules under oxygenated and anoxic conditions. Oxygenated, K-depleted tubules rapidly take up added extracellular potassium accompanied by a simultaneous increase in oxygen consumption. The ATP/O2 ratio was 12.5 +/- 0.7, suggesting a tight coupling between oxidative metabolism (6 ATP/O2) and Na+-K+-ATPase activity (2 K/ATP). On reaching anoxia, the tubules released potassium into the medium, but this rate was accelerated by the addition of ouabain, which indicated that the Na+-K+-ATPase was still operative in anoxia. Because 10 min of anoxia led to only a 15.7% decline in potassium content, a new steady state of potassium uptake and leakage must be reached during anoxia. Anaerobic metabolism maintained 73% of cellular ATP during 10 min of anoxia. Exposure of anoxic tubules to iodoacetate produced a 57% decline in ATP levels and a 33% decline in potassium content, which indicated that glycolysis is an important pathway in supplying energy during anaerobiosis.
在有氧和无氧条件下，测定兔髓质厚升支小管悬浮液中的钠钾ATP酶活性。在有氧、低钾的小管中，添加的细胞外钾被迅速摄取，同时耗氧量增加。ATP/O₂ 比值为12.5±0.7，表明氧化代谢（6ATP/O₂）与钠钾ATP酶活性（2K/ATP）之间存在紧密偶联。进入缺氧状态后，小管将钾释放到培养基中，但哇巴因的添加加速了这一速率，这表明钠钾ATP酶在缺氧状态下仍有活性。由于10分钟的缺氧仅导致钾含量下降15.7%，因此在缺氧期间必须达到钾摄取和泄漏的新稳态。在10分钟的缺氧期间，无氧代谢维持了73%的细胞ATP。将缺氧的小管暴露于碘乙酸中，ATP水平下降57%，钾含量下降33%，这表明糖酵解是无氧状态下提供能量的重要途径。
