Bussolati O, Uggeri J, Belletti S, Dall'Asta V, Gazzola G C
Isituto di Patologia Generale, Università degli Studi di Parma, Italy.
FASEB J. 1996 Jun;10(8):920-6. doi: 10.1096/fasebj.10.8.8666170.
It has been known for several years that the triggering of cell proliferation is associated with an increase of the activity of Na,K,Cl cotransport and of transport system A for neutral amino acids. These systems are also enhanced during the volume recovery of hypertonically shrunk cells. We demonstrate here that during the cell cycle of NIH3T3 cells, an increase in cell volume is associated with an enhanced cell content of potassium and amino acids. Bumetanide delays cell cycle progression and hampers volume increase. The nonmetabolizable analog 2-methylamino-isobutyric acid, a specific substrate of system A, can partially substitute natural amino acids accumulated during the cell cycle as intracellular osmolytes. It is therefore proposed that the stimulation of Na,K,Cl cotransport and of system A, observed in proliferating cells, causes an expansion of cell volume through an enhanced intracellular accumulation of both inorganic and organic osmolytes and the concurrent, osmotically obliged uptake of water.
数年来人们已经知道，细胞增殖的触发与钠钾氯协同转运体以及中性氨基酸转运系统A的活性增加有关。在高渗收缩细胞的体积恢复过程中，这些系统也会增强。我们在此证明，在NIH3T3细胞的细胞周期中，细胞体积的增加与细胞内钾和氨基酸含量的增加有关。布美他尼会延迟细胞周期进程并阻碍体积增加。系统A的特异性底物、不可代谢的类似物2-甲基氨基异丁酸可以部分替代细胞周期中积累的天然氨基酸作为细胞内渗透剂。因此有人提出，在增殖细胞中观察到的钠钾氯协同转运体和系统A的刺激，通过增强无机和有机渗透剂在细胞内的积累以及同时发生的、因渗透压而产生的水摄取，导致细胞体积膨胀。
