Aim: Hepatoma-derived growth factor (HDGF) is a heparin-binding protein, which has been suggested to be involved in the development of kidneys, the cardiovascular system and the liver. We have shown that HDGF is highly expressed in parenchymal hepatocytes in the developing liver and promotes fetal hepatocyte proliferation. In the present study, we asked whether HDGF expression was related to liver regeneration.
Methods: We examined the mRNA and protein expressions of HDGF in two liver regeneration models. In addition, cellular distribution of HDGF in the regenerating liver was investigated by immunohistochemistry.
Results: In the carbon tetrachloride (CCl(4))-treated liver, HDGF expression was induced and the peak was detected at 24 h after the CCl(4 )injection. HDGF expression was also enhanced in the hepatectomy model and the peak was detected at 12 h after surgery. The increased expression of HDGF protein was also confirmed by western blotting. Expression of the HDGF gene in the regenerating liver was dominantly detected in parenchymal hepatocytes.
Conclusion: These findings showed that HDGF expression was induced in parenchymal hepatocytes before the DNA synthesis in the regenerating liver, suggesting the possible involvement of HDGF in liver regeneration as an autocrine factor.