Although fibroblast growth factor 1 (FGF-1) (formerly cyte growth. 1 Besides HGF, transforming growth factor known as acidic FGF) but not FGF-2 (or basic FGF), has a and EGF, fibroblast growth factor 1 (FGF-1) has been been suggested to play a pathophysiological role in liver suggested to play important roles in liver regeneration regeneration, its clinical application has been restricted in situ, because its transcript was found to be induced by its limited mitogenecity and heparin dependence. We immediately after partial hepatechtomy, 5 an experireport here that a chimeric human FGF protein, FGFmental model of liver regeneration. Although the sig-C(1211), is a heparin-independent potent mitogen for nificance of this observation had been underestimated liver parenchymal cells both in vitro and in vivo. In the because of the experimental conditions that did not presence of serum and physiological concentration of allow FGF-1 to exert its full mitogenic activity, 5-7 we insulin, FGF-C(1211) by itself induces as much as 55% of have reported recently that FGF-1 is indeed a potent hepatocytes in culture to proliferate and up to 88% when used in combination with hepatocyte growth factor or growth factor for hepatocytes in the presence of serum epidermal growth factor. Furthermore, hepatocytes nuand physiological concentrations of insulin. 8 Thus, clear labeling in vivo with bromodeoxyuridine was FGF-1 is considered to be a physiological modulator of markedly enhanced when FGF-C(1211) was injected inliver regeneration. However, the application of human travenously into carbon tetrachloride-administered FGF-1 to stimulate proliferation of human liver cells mice. Because FGF-C(1211) is heparin independent and has been limited, because the recombinant human nonantigenic, it has potential for clinical and preclinical FGF-1 does not effectively stimulate hepatocyte growth applications. (HEPATOLOGY 1996;23:316-319.) NJ) column by washing with 0.7 mol/L NaCl, 20 mmol/L Tris-HCl (pH 7.4) and eluting with 1.5 mol/L NaCl in 20 mmol/L Tris-HCl (pH 7.4). The protein was further purified on a Hi-Abbreviations: HGF, hepatocyte growth factor; EGF, epidermal growth factrap-heparin HPLC column (Pharmacia) by linear gradient tor; FGF-1, fibroblast growth factor 1.