Potassium fluxes in the rat reticulocyte. Ouabain sensitivity and changes during maturation.
Potassium fluxes in the rat reticulocyte. Ouabain sensitivity and changes during maturation.
复制标题
大鼠网织红细胞中的钾通量。
DOI：
10.1016/0005-2736(81)90167-x
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Loeb,JN
中科院分区：
文献类型：
--
作者：
Furukawa,H;Bilezikian,JP;Loeb,JN
大鼠网织红细胞的K+周转率显著增加，内流和外流的速率都比成年细胞的相应速率增加了约3倍。尽管在成熟过程中细胞内K+浓度没有任何明显的变化，但仍能观察到这些加速的通量。在网织红细胞和成熟红细胞中，K+内流主动转运过程的定性特征似乎与K+敏感性和哇巴因敏感性作为外部K+浓度的函数是相同的。然而，单位体积细胞中哇巴因结合位点的数量在网织红细胞中增加了大约三倍，因此与观察到的这些细胞中活性K+内流的增强程度很好地相关。对于网织红细胞和成熟红细胞，当外部K+浓度远低于1 mM时，哇巴因敏感型K+内流的半最大速率被观察到。结论：网织红细胞K+积累率的增加可以定量地归因于泵单位的增加，这些泵单位在质量上与成熟细胞中的泵单位相同，并且在正常大鼠血浆中存在的环境K+浓度下以接近最大的速率发挥作用。
K+turnover is markedly enhanced in the rat reticulocyte, both influx and efflux rates being increased by factors of approximately 3 over the corresponding rates in adult cells. These accelerated fluxes are observed despite the absence of any appreciable change in intracellular K+concentration during the course of maturation. Qualitative characteristics of the active transport process for K+influx appear to be identical in reticulocytes and mature erythrocytes with regard both to K+sensitivity, and to ouabain sensitivity as a function of external K+concentration. The number of ouabain binding sites per unit volume of cells, however, is increased by a factor of approximately three in the reticulocyte and thus correlates well with the observed degree of enhancement of active K+influx in these cells. Half-maximal rates of ouabain-sensitive K+influx are observed at external K+concentrations well below 1 mM for both reticulocytes and mature erythrocytes. It is concluded that the enhanced rate of K+accumulation in the reticulocyte can be quantitatively attributed to an increased number of pump units which are qualitatively identical to those in the mature cell, and which function at a near-maximal rate at the ambient K+concentration present in normal rat plasma.