Wilson D F, Erecińska M, Drown C, Silver I A
Am J Physiol. 1977 Nov;233(5):C135-40. doi: 10.1152/ajpcell.1977.233.5.C135.
Simultaneous measurements of the mitochondrial [NAD+]/[NADH], the cytoplasmic [ATP]/[ADP] x [Pi], and the respiratory rate were carried out in suspensions of cultured kidney cells in a range of defined oxygen tensions. The results show that as the extracellular oxygen concentration falls there is a decrease in the respiratory rate, which is accompanied by a decrease in the [ATP]/[ADP] and a progressive reduction of cytochrome c. Even at low O2 tensions the mitochondrial respiratory chain between the NAD couple and cytochrome c remains at near equilibrium with the ATP synthesizing reactions. It is concluded that limited oxygen supply affects cellular metabolism at much higher concentrations than the P50 value for the oxygen dependence of respiration, but the respiratory rate remains relatively unchanged due to compensatory changes in the [ATP]/[ADP] X [Pi] and progressive reduction of cytochrome c. These metabolic changes may form a basis for the phenomenon of tissue oxygen sensing at near physiological oxygen tensions.
在一系列确定的氧张力条件下，对培养的肾细胞悬液中的线粒体[NAD⁺]/[NADH]、细胞质[ATP]/[ADP]×[Pi]以及呼吸速率进行了同步测量。结果表明，随着细胞外氧浓度降低，呼吸速率下降，同时伴有[ATP]/[ADP]降低以及细胞色素c逐渐减少。即使在低氧张力条件下，NAD偶联与细胞色素c之间的线粒体呼吸链仍与ATP合成反应保持接近平衡。得出的结论是，有限的氧供应在比呼吸氧依赖性的P50值高得多的浓度下影响细胞代谢，但由于[ATP]/[ADP]×[Pi]的代偿性变化以及细胞色素c的逐渐减少，呼吸速率保持相对不变。这些代谢变化可能构成在接近生理氧张力时组织氧感知现象的基础。
