EGF responsiveness of hepatocytes after partial hepatectomy

We investigate the effect of EGF on IP 3 production, PLCγ phosphorylation, calcium transients in rat hepatocytes isolated in quiescent liver (G 0 phase of cell cycle) and at 4 h (G 1 phase of cell cycle) and 24 h (M phase of cell cycle) after partial hepatectomy. Our results show that EGF does not utilize IP 3 and calcium as its signal transduction molecules when the hepatocytes are in vivo stimulated to entry in the cell cycle. In particular the growth factor does not phosphorylate PLCγ and induces a decrease in IP 3 content. These data suggest that EGF utilizes different signal transduction to send information from receptor to nucleus during PH with respect to the quiescent liver.