Asymmetry of Na-K-Cl cotransport in human erythrocytes.
Asymmetry of Na-K-Cl cotransport in human erythrocytes.
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人红细胞中 Na-K-Cl 共转运的不对称性。
DOI：
10.1152/ajpcell.1988.254.2.c243
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Dunham,PB
中科院分区：
文献类型：
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作者：
Kracke,GR;Anatra,MA;Dunham,PB
本文用Na、K净流入和净流出的方法研究了人红细胞Na-K-Cl共转运系统。钾的内流被证明是由钠和钠的内流被K刺激，满足基本标准的共转运。此外，这些相互刺激的阳离子流入的化学计量比为1：1，并完全抑制呋塞米，这些结果也是一致的共转运。此外，相互刺激的内流完全依赖于Cl，因为当用硝酸盐代替Cl时，它们就消失了。与此相反，cotransport，定义为相互依赖的流量，没有检测到在向外的方向上的细胞Na和K浓度范围从0到50 mmol/l的细胞。然而，共转运途径似乎确实介导了Na刺激的K流出（但没有K刺激的Na流出），以及Na和K的呋塞米可降解流出。硝酸盐（而不是硫酸盐）似乎取代氯化物在促进钠刺激钾外流。因此，在人类红细胞的钠-钾-氯共转运系统本质上是不对称的，并介导耦合阳离子通量容易只在向内的方向。
The Na-K-Cl cotransport system in human erythrocytes was studied by measuring net influxes and effluxes of Na and K. The influx of K was shown to be stimulated by Na and the influx of Na was stimulated by K, satisfying the fundamental criterion of cotransport. In addition, these mutually stimulating cation influxes had a stoichiometry of 1:1 and were entirely inhibited by furosemide; these results are also consistent with cotransport. Furthermore, the mutually stimulating influxes were entirely dependent on Cl, since they were abolished when nitrate was substituted for Cl. In contrast, cotransport, defined by mutual dependence of fluxes, was not detected in the outward direction over a range of cellular Na and K concentrations from 0 to 50 mmol/l cells. The cotransport pathway did, however, appear to mediate a Na-stimulated K efflux (but no K-stimulated Na efflux), and furosemide-inhibitable effluxes of both Na and K. Nitrate (but not sulfate) appeared to substitute for chloride in promoting Na-stimulated K efflux. Thus the Na-K-Cl cotransport system in human red cells is intrinsically asymmetric, and mediates coupled cation fluxes readily only in the inward direction.