Hiraki Y, Inoue H, Kato Y, Fukuya M, Suzuki F
Department of Biochemistry and Calcified-Tissue Metabolism, Faculty of Dentistry, Osaka University, Japan.
Mol Cell Biochem. 1987 Aug;76(2):185-93. doi: 10.1007/BF00223483.
The somatomedin-like growth factors cartilage-derived factor (CDF) and multiplication-stimulating activity (MSA) stimulate DNA synthesis and proliferation of rabbit costal chondrocytes under serum-free conditions. Previously, we suggested that CDF and MSA act on chondrocytes in an early G1 phase to stimulate DNA synthesis. CDF and MSA have synergistic effects with epidermal growth factor (EGF) or fibroblast growth factor (FGF) in stimulating DNA synthesis of the cells. The mode of combined action of CDF or MSA with EGF or FGF in chondrocytes was studied by sequential treatments with these agents. EGF or FGF had synergistic effects with CDF or MSA in stimulating DNA synthesis, even when added 10 h after the latter. Synergism was also observed in cells pretreated with CDF or MSA; That is, the cultures were treated for 5 h with CDF or MSA and then washed, and treated with FGF or EGF. However, when CDF or MSA was added more than 5 h after EGF or FGF, no synergism of effects was observed. These findings suggest that the cultured chondrocytes become activated to interact with FGF or EGF for commitment to DNA synthesis when they are exposed to somatomedin-like growth factors at an early stage in the G1 phase. Thus chondrocytes are under a different mechanism of growth control from fibroblastic cells.
类生长调节素样生长因子软骨衍生因子（CDF）和促增殖活性因子（MSA）在无血清条件下可刺激兔肋软骨细胞的DNA合成和增殖。此前，我们认为CDF和MSA作用于处于G1期早期的软骨细胞以刺激DNA合成。CDF和MSA在刺激细胞DNA合成方面与表皮生长因子（EGF）或成纤维细胞生长因子（FGF）具有协同作用。通过用这些因子进行序贯处理，研究了CDF或MSA与EGF或FGF在软骨细胞中的联合作用模式。即使在CDF或MSA加入10小时后再加入EGF或FGF，它们在刺激DNA合成方面仍具有协同作用。在用CDF或MSA预处理的细胞中也观察到了协同作用；也就是说，培养物先用CDF或MSA处理5小时，然后洗涤，再用FGF或EGF处理。然而，当在EGF或FGF加入后5小时以上再加入CDF或MSA时，未观察到效应的协同作用。这些发现表明，当培养的软骨细胞在G1期早期暴露于类生长调节素样生长因子时，它们会被激活以与FGF或EGF相互作用从而启动DNA合成。因此，软骨细胞的生长调控机制与成纤维细胞不同。
