The Role of a New Hepatocyte Growth Factor in Liver Regeneration

小鼠血清肝细胞生长刺激活性显着增加四氯化碳给药后24小时，然后下降。该活性的时程与血清丙氨酸和天冬氨酸转氨酶活性的时程平行。肝提取物中的肝细胞生长刺激活性在未处理的小鼠中较低，但在四氯化碳后增加。肝毒素后12 h和24 h可检测到增加。给药后48 h达最大值，随后逐渐下降。肝DNA合成开始上升，并分别在肝毒素后36 h和48 h达到最高。因此，在四氯化碳处理的小鼠中，在肝再生之前，血清和肝脏中的肝细胞生长刺激活性增加。肝损伤后血清和肝脏活性的升高可能在促进体内肝细胞增殖中起重要作用。用硫酸铵分级分离，经Affi-Gel Blue、肝素-Sepharose和S-Sepharose层析，从肝毒素处理的小鼠肝上清中纯化出小鼠肝细胞生长因子（mHGF），纯化倍数约为280，000倍，得率为21%。在非还原条件下纯化的mHGF的SDS-聚丙烯酰胺凝胶电泳（PAGE）显示单一条带，分子量（MW）为76 K，而还原mHGF的SDS-PAGE检测到两条条带，分子量为62 K和31 K，表明mHGF是异二聚体。mHGF与hHGF一样有效地刺激培养肝细胞的DNA合成。mHGF的作用与EGF和酸性FGF的最大作用相加，与胰岛素的最大作用协同，但与hHGF的最大作用不协同。因此，mHGF的性质与hHGF的性质相似。mHGF可能是hHGF样因子，与hHGF有一些结构上的不同，因为mHGF的活性不被中和hHGF活性的兔抗hHGF抗血清所抑制。

A mouse serum hepatocyte growth-stimulating activity markedly increased 24 h after carbon tetrachloride administration and then decreased. This time course of the activity was paralled with those of serum alanine and aspartate aminotransferses activities. hepatocyte growth-stimulating activity in liver extracts was low in untreated mice, but increased after carbon tetrachloride. The increase was detectable 12 h and marked 24 h after the hepatotoxin. It was maximal 48 h after the administration and then dropped gradually. Liver DNA synthesis began to rise and was highest 36 h and 48 h, respectively, after the hepatotoxin. Thus, the hepatocyte growth-stimulating activity in serum and liver increased prior to liver regeneration in carbon tetrachloride-treated mice. The elevated serum and liver activities may play an important role in promoting proliferation of liver cells in vivo subsequent to hepatic injury. Mouse hepatocyte growth factor (mHGF) was purified about 280,000-fold with 21% yield form the liver supernatant of mice treated with the hepatotoxin by ammonium sulfate fractionation followed by chromatography on Affi-Gel Blue, heparin-Sepharose and S-Sepharose. SDS-PolyacrylAmide Gel Electrophoresis (PAGE) of purified mHGF under nonreducing conditions showed a single band with a Molecular Weight (MW) of 76K, while two bands with MWs of 62K and 31K were detected after SDS-PAGE of reduced mHGF, showing that mHGF is a heterodimer. mHGF stimulated DNA synthesis of cultured hepatocytes as effectively as hHGF. The effect of mHGF was additive with the maximal effects of EGF and acidic FGF and synergistic with that of insulin, but not with the maximal effect of hHGF. Thus, the properties of mHGF are similar to those of hHGF. mHGF may be a hHGF-like factor with some structural differences from hHGF, because the activity of mHGF was not inhibited by rabbit anti-hHGF antiserum which neutralizes the hHGF activity.