Significance of growth factors for Hepatocyte proliferation and functions

虽然分化的细胞功能被认为在细胞增殖过程中受到抑制，但最近的研究表明，几种有丝分裂原刺激肝细胞的蛋白质产生和增殖。我们研究了肝细胞生长因子（HGF）和转化生长因子α (TGFα)刺激肝细胞增殖和蛋白生成过程中细胞内信号转导的意义。在低密度培养的肝细胞中，EGF/TGFα受体的激活和PI3K信号通路可能通过p70S6激酶的激活参与了HGF对DNA合成的上调。这种生长因子也通过激活PI3K通路刺激高密度培养的肝细胞产生白蛋白，但不依赖于TGFα。这些结果表明，根据生理条件，PI3K通路可以在HGF刺激的肝细胞中介导细胞增殖或蛋白质产生。

While differentiated cellular functions are thought to be suppressed during cell proliferation, recent studies have revealed that several mitogens stimulate protein production in hepatocytes as well as proliferation. We studied the significance of intracellular signal transduction during proliferation and protein production in hepatocytes stimulated by hepatocyte growth factor (HGF) and transforming growth factor α (TGFα). In hepatocytes cultured at low density, the EGF/TGFα receptor activation and the PI3K signaling pathway, perhaps through the activation of p70S6 kinase, may contribute to the up-regulation of DNA synthesis by HGF. This growth factor also stimulates albumin production in hepatocytes cultured at high density, also via the activation of the PI3K pathway but independent of TGFα These results suggest that, depending on the physiological conditions, PI3K pathways can mediate either cell proliferation or protein production in hepatocytes stimulated by HGF.