Insulin stimulates amino acid transport by alveolar type II epithelial cells in primary culture.
Insulin stimulates amino acid transport by alveolar type II epithelial cells in primary culture.
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胰岛素刺激原代培养物中肺泡 II 型上皮细胞的氨基酸转运。
DOI：
10.1164/arrd.1987.135.3.617
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Mason,RJ
中科院分区：
文献类型：
--
作者：
Sugahara,K;Voelker,DR;Mason,RJ
本实验旨在研究胰岛素对成年大鼠肺泡II型上皮细胞氨基酸转运的影响。通过测量非代谢氨基酸α-氨基异丁酸（AIB）的摄取来确定氨基酸转运的初始速率。肺泡II型上皮细胞运输AIB钠依赖的过程中，显示饱和动力学。胰岛素刺激的0.1 mM AIB转运（82.3 ± 15.0%，平均值± SE，n = 4），半数最大有效胰岛素浓度为2.2 ± 1.0 ng/ml（平均值± SE），这在大鼠血清胰岛素浓度的生理范围内。对AIB转运的动力学分析表明，胰岛素使AIB转运速度从6.7 ± 1.2nmol/106 cells/min增加到9.3 ± 1.8nmol/106 cells/min，而对Km值（5.2 ± 0.8mM）无影响。α-（甲氨基）异丁酸，氨基酸转运系统A的特异性底物，抑制钠依赖性和胰岛素调节的AIB的运输。因此，肺泡II型上皮细胞在钠依赖性过程中转运氨基酸，胰岛素刺激这种转运。本研究表明，胰岛素可能在调节肺泡II型上皮细胞的氨基酸转运中发挥生理作用。
The present experiments were designed to investigate the effect of insulin on amino acid transport by alveolar type II epithelial cells isolated from adult rats. The initial rates of amino acid transport were determined by measuring the uptake of the nonmetabolizable amino acid, α-aminoisobutyric acid (AIB). Alveolar type II epithelial cells transported AIB by a sodium-dependent process that displayed saturable kinetics. Insulin stimulated transport of 0.1 mM AIB (82.3 ± 15.0%, mean ± SE, n = 4) with a half-maximally effective insulin concentration of 2.2 ± 1.0 ng/ml (mean ± SE), which is within the physiologic range of rat serum insulin concentration. Kinetic analysis of AIB transport showed that insulin increased the from 6.7 ± 1.2 nmol/106cells/min to 9.3 ± 1.8 nmol/106cells/min and had no effect on theKmvalue (5.2 ± 0.8 mM). Alpha-(methylamino) isobutyric acid, a specific substrate for amino acid transport system A, inhibited both the sodium-dependent and insulin-modulated transport of AIB. Thus, alveolar type II epithelial cells transport amino acids in a sodium-dependent process and insulin stimulates this transport. The present study indicates that insulin may play a physiologic role in regulating amino acid transport in alveolar type II epithelial cells.