Tang B, Jeoung D I, Sonenberg M
Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
Endocrinology. 1995 Jul;136(7):3062-9. doi: 10.1210/endo.136.7.7789333.
Cellular growth- and cyclin D expression-regulating activities of GH and insulin were investigated in 3T3-F442A preadipose cells under serum-free culture conditions. The present report provides evidence that the proliferative potential of 3T3-F442A cells is reduced by GH in a time- and concentration-dependent manner based on [3H]thymidine incorporation assay and cell cycle analysis. In contrast, treatment of 3T3-F442A cells with insulin resulted in cellular proliferation. The insulin-induced proliferation of 3T3-F442A cells was diminished in the presence of GH. In an effort to define biochemical events relevant to the regulatory activities of GH and insulin on the proliferation of 3T3-F442A cells, the effects of these peptides on the expression of cyclin D were studied using Western blotting. Treatment of 3T3-F442A cells with insulin led to an increase in cyclin D expression relative to that in untreated cells. The insulin-elicited expression of cyclin D was time and dose dependent. In addition, the ability of insulin to induce cyclin D expression was reduced by GH. Our experimental results indicate that proliferation of 3T3-F442A cells was regulated by GH and insulin. The regulatory effects of GH and insulin are mediated at least in part by the alternating expression of cyclin D protein.
在无血清培养条件下，研究了生长激素（GH）和胰岛素对3T3-F442A前脂肪细胞的细胞生长及细胞周期蛋白D表达的调节活性。本报告提供的证据表明，基于[3H]胸腺嘧啶核苷掺入试验和细胞周期分析，GH以时间和浓度依赖性方式降低3T3-F442A细胞的增殖潜能。相反，用胰岛素处理3T3-F442A细胞会导致细胞增殖。在存在GH的情况下，胰岛素诱导的3T3-F442A细胞增殖减少。为了确定与GH和胰岛素对3T3-F442A细胞增殖的调节活性相关的生化事件，使用蛋白质印迹法研究了这些肽对细胞周期蛋白D表达的影响。用胰岛素处理3T3-F442A细胞导致细胞周期蛋白D表达相对于未处理细胞增加。胰岛素诱导的细胞周期蛋白D表达具有时间和剂量依赖性。此外，GH降低了胰岛素诱导细胞周期蛋白D表达的能力。我们的实验结果表明，3T3-F442A细胞的增殖受GH和胰岛素调节。GH和胰岛素的调节作用至少部分是由细胞周期蛋白D蛋白的交替表达介导的。
