Stimulation of DNA and RNA synthesis in the liver of hepatectomized rats by fractions of liver cytosol and conditioned media obtained during cultivation of rat liver explants

: Heat resistant fractions stimulating proliferation (PSF) were identified in the fractions of rat liver cytosol after 70% hepatectomy as well as in the medium harvested after cultivation of rat liver explants. The PSF augmented considerably the rate of DNA synthesis, it increased synthesis and transport of rapidly labelled RNA as well as the level of mitotic activity in rat liver tissue resected by 30% and 80%. Role of the PSF in regulation and acceleration of regeneration processes in the residual parts of liver tissue, remained after hepatectomy, is discussed.