成熟的肝脏是代谢极旺盛的器官，但其肝细胞则处于静息期（Ｇｏ期），即细胞几乎不发生分裂增殖。然而，人胎肝正处于旺盛生长状态，其肝细胞能合成ＤＮＡ和进行有丝分裂，并迅速增殖或再生，与肝生长调控有关的因子很多，目前研究较清楚，在肝细胞分裂增殖中起主要作用的有两种因子，即肝刺激因子（ＨＳＳ）和肝细胞生长因子（ＨＧＦ）。我们认为人胎肝内同时存在这两种因子，且为两种不同的促细胞分裂剂。 Mature liver is extremely prosperous organ, but the liver cells are in the resting period (Go phase), that is, the cells hardly divide and proliferate. However, the human fetal liver is in a state of vigorous growth, and its liver cells can synthesize DNA and mitosis, and rapidly proliferate or regenerate. There are many factors involved in the regulation of liver growth. Currently, studies clearly show that it plays a major role in hepatocyte division and proliferation There are two factors, namely, hepatic stimulating factor (HSS) and hepatocyte growth factor (HGF). We think both of these two factors exist in human fetal liver, and are two different mitogenic agents.