Effects of human neonatal serum on DNA synthesis in suckling and adult rat hepatocytes in primary culture

Abstract

The effect of human neonatal serum on DNA synthesis in suckling and adult rat hepatocytes in primary culture was investigated to characterize growth regulating factors of the liver in neonates and to confirm whether the stimulatory factor is human hepatocyte growth factor (hHGF). Neonatal serum stimulated DNA synthesis of both adult and suckling rat hepatocytes. The stimulatory effect was dose-dependent up to 20% in volume. The molecular weight of the stimulatory substance in neonatal serum was between 12,500 and 25,000, as estimated by gel filtration. Its activity was stable after heating at 56 degrees C for 20 min, but was lost after heating at 90 degrees C for 30 s, and easily passed through S- or heparin-Sepharose columns. The concentration of hHGF quantified by ELISA was too low to stimulate DNA synthesis in vitro. Biological and biochemical properties of the growth stimulatory activity in neonatal serum differed from that of hHGF. The presence of other growth factors in human neonatal serum for suckling and adult hepatocytes was suggested.