Insulin stimulation of (Na+,K+)-adenosine triphosphatase-dependent 86Rb+ uptake in rat adipocytes.
Insulin stimulation of (Na+,K+)-adenosine triphosphatase-dependent 86Rb+ uptake in rat adipocytes.
复制标题
胰岛素刺激大鼠脂肪细胞中 (Na ,K )-腺苷三磷酸酶依赖性 86Rb 摄取。
DOI：
10.1016/s0021-9258(19)70397-4
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
G. Guidotti
中科院分区：
文献类型：
--
作者：
M. Resh;R. Nemenoff;G. Guidotti
胰岛素刺激大鼠脂肪细胞对86Rb+（一种K+类似物）的摄取，增加细胞内钾的稳态浓度。一半最大刺激发生在胰岛素浓度为200pm时。基础和胰岛素刺激的86Rb+转运速率都依赖于外源K+和Na+的浓度，并且被10(-3)M瓦巴因和10(-3)M KCN抑制了90%，这表明激素激活了(Na+,K+)- atp酶。胰岛素对22Na+的进入和86Rb+的退出没有影响。动力学分析表明胰岛素通过增加86Rb+进入的最大速度Vmax起作用。瓦巴因对Rb+摄取速率的抑制作用最好用双相抑制曲线来描述。对完整细胞结合的Scatchard分析表明，结合位点具有多个亲和力。胰岛素只刺激对瓦巴因有高亲和力的铷转运位点。刺激需要胰岛素与完整的细胞表面受体结合，因为胰蛋白酶化是可逆的。我们认为(Na+,K+)- atp酶对86Rb+的摄取是脂肪细胞中胰岛素敏感的膜转运过程。
Insulin stimulated the uptake of 86Rb+ (a K+ analog) in rat adipocytes and increased the steady state concentration of intracellular potassium. Half-maximal stimulation occurred at an insulin concentration of 200 pM. Both basal- and insulin-stimulated 86Rb+ transport rates depended on the concentration of external K+, external Na+, and were 90% inhibited by 10(-3) M ouabain and 10(-3) M KCN, indicating that the hormone was activating the (Na+,K+)-ATPase. Insulin had no effect on the entry of 22Na+ or exit of 86Rb+. Kinetic analysis demonstrated that insulin acted by increasing the maximum velocity, Vmax, of 86Rb+ entry. Inhibition of the rate of Rb+ uptake by ouabain was best described by a biphasic inhibition curve. Scatchard analysis of ouabain binding to intact cells indicated binding sites with multiple affinities. Only the rubidium transport sites which exhibited a high affinity for ouabain were stimulated by insulin. Stimulation required insulin binding to an intact cell surface receptor, as it was reversible by trypsinization. We conclude that the uptake of 86Rb+ by the (Na+,K+)-ATPase is an insulin-sensitive membrane transport process in the fat cell.