de Asua L J, Rozengurt E, Dulbecco R
Proc Natl Acad Sci U S A. 1974 Jan;71(1):96-8. doi: 10.1073/pnas.71.1.96.
A kinetic study of the early changes in uridine- and phosphate-transport rates and 3':5'-cyclic AMP levels induced by the addition of serum to quiescent 3T3 cells revealed that the increase in phosphate uptake and the decrease in the intracellular concentration of 3':5'-cyclic AMP immediately follow the addition of serum. In contrast, the increase in uridine transport occurred after a lag of several minutes and was clearly preceded by the other changes. The activation of phosphate transport involved an increase in V(max), while a more complex pattern was observed for uridine transport. A possible role of phosphate in connection with the other early events was also studied. The addition of phosphate to quiescent cells produced a time-dependent decrease in 3':5'-cyclic AMP levels and this ion was required for full activation of uridine transport by serum. The results show that the increase in phosphate transport is a primary event in the reinitiation of growth and suggest that the increase in phosphate transport may be connected with subsequent metabolic steps.
一项关于向静止的3T3细胞添加血清后尿苷和磷酸盐转运速率以及3':5'-环磷酸腺苷水平早期变化的动力学研究表明，磷酸盐摄取的增加和细胞内3':5'-环磷酸腺苷浓度的降低在添加血清后立即发生。相比之下，尿苷转运的增加在几分钟的延迟后才出现，并且明显滞后于其他变化。磷酸盐转运的激活涉及V(max)的增加，而尿苷转运则表现出更复杂的模式。还研究了磷酸盐与其他早期事件相关的可能作用。向静止细胞添加磷酸盐会导致3':5'-环磷酸腺苷水平随时间下降，并且该离子是血清完全激活尿苷转运所必需的。结果表明，磷酸盐转运的增加是生长重新启动的主要事件，并表明磷酸盐转运的增加可能与随后的代谢步骤有关。
