PURIFICATION AND CHARACTERIZATION OF HEPATOCYTE GROWTH-FACTOR FROM INJURED LIVER OF CARBON TETRACHLORIDE-TREATED RATS

A hepatocyte growth factor (HGF)-like substance that strongly stimulated DNA synthesis of adult rat hepatocytes in primary culture was found to increase markedly in liver of rats treated with carbon tetrachloride (CCl4). This increase of HGF-like activity was time- and dose-dependent, and 36 h after a dose of CCl4 of 0.2 ml per 100 g body weight the activity was about 20-times the normal level. The extent of induction of HGF-like factor correlated well with the extent of liver damage. The HGF-like factor was purified to homogeneity from the liver of CCl4-treated rats by a four-step procedure. The purified HGF-like factor had a molecular weight of 82-85 kDa, as estimated by SDS-PAGE, and was a heterodimer composed of a large subunit of about 69 kDa and a small subunit of 34 kDa linked by disulfide bridges. This factor had similar biological and chemical properties to HGF purified from rat platelets. Moreover, the N-terminal amino acid sequence of its 34-kDa subunit was identical to that of the small subunit of rat HGF. These findings indicate that the HGF-like factor in damaged liver of CCl4-treated rats is HGF and that liver itself can produce HGF when injured.