Stiles C D, Isberg R R, Pledger W J, Antoniades H N, Scher C D
J Cell Physiol. 1979 Jun;99(3):395-405. doi: 10.1002/jcp.1040990314.
Much controversy regarding the relationship between nutrients and serum in regulation of cell growth can be reconciled by recognizing that serum contains multiple factors which regulate different events in the cell cycle. Serum was fractionated into a platelet-derived growth factor (PDGF), which induces cells to become competent to synthesize DNA, and plasma which allows competent cells to traverse G0/G1 and enter the S phase. Nutrients are not required for the cellular response to PDGF; however amino acids are required for plasma to promote the entry of PDGF-treated, competent cells into S phase. The nutrient independent, PDGF-modulated, growth regulatory event (competence) is located 12 hours prior to the G1/S phase boundary in quiescent, density-arrested Balb/c-3T3 cells. The nutrient dependent, plasma-modulated event is located six hours prior to the G1/S phase boundary and corresponds in concentration of amino acids required for DNA synthesis. Infection of density-arrested Balb/c3T3 cells with SV40 overrides both the nutrient independent and the nutrient dependent growth regulatory events.
关于营养素与血清在调节细胞生长中关系的诸多争议，可以通过认识到血清含有多种调节细胞周期中不同事件的因子来解决。血清被分离为血小板衍生生长因子（PDGF），它诱导细胞具备合成DNA的能力，以及血浆，血浆使具备能力的细胞穿过G0/G1期并进入S期。细胞对PDGF的反应不需要营养素；然而，血浆促进经PDGF处理且具备能力的细胞进入S期需要氨基酸。在静止、密度抑制的Balb/c - 3T3细胞中，与营养素无关、由PDGF调节的生长调节事件（具备能力）发生在G1/S期边界前12小时。与营养素有关、由血浆调节的事件发生在G1/S期边界前6小时，并与DNA合成所需的氨基酸浓度相对应。用SV40感染密度抑制的Balb/c3T3细胞会使与营养素无关和与营养素有关的生长调节事件均失效。
