Ross R
Agents Actions Suppl. 1980;7:81-4.
Growth factors have been isolated from three cell types associated with the vascular system; the platelet, the monocyte/macrophage, and the endothelial cell. Each of these mitogens appears to have different characteristics. The platelet-derived growth factor is a cationic protein (pI 9.8) that is heat stable, of molecular weight approx. 30,000 and is located in the alpha granules of the platelet. The growth factors derived from the monocyte/macrophage and the endothelial cell each appear to be distinct and different proteins. Each of these factors was discovered as a result of the ability to induce quiescence in the G1/G0 state of cells in culture, that can be readily induced in the presence of cell free plasma-derived serum in the culture medium. Cells such as fibroblasts, smooth muscle, 3T3 cells and glial cells will remain quiescent in culture medium containing plasma-derived serum for periods up to 6 weeks. Stimulation by the platelet-derived growth factor or macrophage-derived growth factor, will commit these cells to enter S and begin cell cycle traverse. Inhibition of platelet function in vivo can be shown to inhibit intimal smooth muscle proliferation in response to endothelial injury. Thus, each of these factors may play important roles in the process of initiation of fibroplasia in wound repair, smooth muscle proliferation in atherogenesis and endothelial proliferation in response to injury.
生长因子已从与血管系统相关的三种细胞类型中分离出来，即血小板、单核细胞/巨噬细胞和内皮细胞。这些促有丝分裂原中的每一种似乎都有不同的特性。血小板衍生生长因子是一种阳离子蛋白（pI 9.8），耐热，分子量约为30,000，位于血小板的α颗粒中。源自单核细胞/巨噬细胞和内皮细胞的生长因子似乎都是独特且不同的蛋白质。这些因子中的每一种都是由于能够诱导培养中的细胞在G1/G0状态下静止而被发现的，在培养基中存在无细胞血浆衍生血清的情况下很容易诱导这种静止状态。成纤维细胞、平滑肌、3T3细胞和神经胶质细胞等细胞在含有血浆衍生血清的培养基中可保持静止长达6周。血小板衍生生长因子或巨噬细胞衍生生长因子的刺激会使这些细胞进入S期并开始细胞周期进程。体内血小板功能的抑制可显示出能抑制内膜平滑肌对内皮损伤的增殖反应。因此，这些因子中的每一种可能在伤口修复中的纤维增生起始过程、动脉粥样硬化形成中的平滑肌增殖以及对损伤的内皮增殖过程中发挥重要作用。
