培养的成纤维细胞中氨基酸转运活性的渗透调节

Osmoregulation of amino acid transport activity in cultured fibroblasts.

作者信息

Tramacere M, Petronini P G, Severini A, Borghetti A F

出版信息

Exp Cell Res. 1984 Mar;151(1):70-9. doi: 10.1016/0014-4827(84)90356-2.

Abstract

The effect of exposure of chick embryo cells to increasing concentrations of Na+ in the culture medium on the subsequent amino acid transport as determined at physiological osmolarity was investigated in detail. It was found that the hyperosmolar treatment stimulated amino acid transport in a dose-dependent manner up to 200 mM Na+. Changes were measurable as early as 1 h after altering Na+ and reached a maximum after 4 h, remaining constant thereafter. The maintenance of this effect required continuous exposure of the cell to high Na+ in the culture medium. Hyperosmolarity-mediated increases in amino acid transport activity by system A have been detected with L-proline and L-alanine. Transport activities of systems ASC and L did not change appreciably after exposure of the cells to high Na+. Inhibition of protein synthesis by cycloheximide or RNA synthesis by actinomycin D (actD) prevented these uptake changes. Kinetic analysis indicated that the stimulation of the activity of transport system A by high Na+ treatment occurred through a mechanism affecting Vmax rather than Km.

摘要

详细研究了将鸡胚细胞暴露于培养基中浓度不断增加的Na⁺下，在生理渗透压下对随后氨基酸转运的影响。结果发现，高达200 mM Na⁺时，高渗处理以剂量依赖方式刺激氨基酸转运。早在改变Na⁺后1小时就可检测到变化，并在4小时后达到最大值，此后保持恒定。这种效应的维持需要细胞持续暴露于培养基中的高Na⁺。已用L-脯氨酸和L-丙氨酸检测到系统A介导的高渗性增加氨基酸转运活性。细胞暴露于高Na⁺后，系统ASC和L的转运活性没有明显变化。用环己酰亚胺抑制蛋白质合成或用放线菌素D（actD）抑制RNA合成可阻止这些摄取变化。动力学分析表明，高Na⁺处理对转运系统A活性的刺激是通过影响Vmax而非Km的机制发生的。