Quantitation of Na/K ATPase pump sites in the rabbit corneal endothelium.
Quantitation of Na/K ATPase pump sites in the rabbit corneal endothelium.
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DOI：
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发表时间：
1984-09
影响因子：
4.4
通讯作者：
D. Geroski;H. Edelhauser
中科院分区：
文献类型：
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作者：
D. Geroski;H. Edelhauser
在这些实验中，结合3 H。用Na/KATP酶特异性抑制剂哇巴因定量测定兔角膜内皮Na/KATP酶泵位点密度。角膜内皮对哇巴因的摄取有两种成分：一种是在哇巴因浓度接近2 × 10（-7）M时饱和（特异性结合），另一种是随着糖苷浓度的增加而线性增加（非特异性摄取）。非特异性摄取可以通过哇巴因与细胞外空间平衡来解释，其通过菊粉空间估计，相当于内皮的13.0 nl/mm 2。内皮哇巴因摄取的饱和组分被K+离子取代，这与该部分结合Na/K ATP酶一致。最大内皮哇巴因结合测量为20.7 fmol/mm 2内皮，其对应于每个细胞3.0 × 10（6）个泵位点。兔角膜内皮中Na/K ATP酶泵位点的密度与报道的几种转运上皮细胞的密度相当。这些数据与已知的角膜内皮功能一致，证实了Na/K ATP酶在内皮液体转运中的重要性。
In these experiments, the binding of 3H . ouabain, a specific inhibitor of Na/K ATPase, was used to quantitate the density of Na/K ATPase pump sites in the rabbit corneal endothelium. The uptake of ouabain by the corneal endothelium shows two components: one that saturates at a ouabain concentration near 2 X 10(-7) M (specific binding), and one component that increases linearly with increasing glycoside concentration (nonspecific uptake). The nonspecific uptake can be accounted for by that ouabain equilibrating with the extracellular space, which, estimated by inulin space, amounts to 13.0 nl/mm2 of endothelium. The saturable component of endothelial ouabain uptake is displaced by K+ ions, which is consistent with this fraction being bound to Na/K ATPase. Maximal endothelial ouabain binding was measured as 20.7 fmoles/mm2 of endothelium, which corresponds to 3.0 X 10(6) pump sites per cell. The density of Na/K ATPase pump sites in the rabbit corneal endothelium is comparable to densities reported for several transporting epithelia. These data are consistent with the known function of the endothelium in corneal deturgescense and corroborate the importance of Na/K ATPase in endothelial fluid transport.