We demonstrated that HGF reduces gap junctional intercellular communication of rat hepatocyte doublets and increases cell spreading. Intercellular communication via gap junctions was markedly reduced in hepatocyte doublets with HGF (20 ng/ml) 3-12 hr after inoculation. Immunocytochemistry revealed spotty localization of connexin 32 on the plasma membrane of 3-hr cultured control hepatocyte doublets, whereas HGF-treated doublets showed significantly less connexin 32 staining. Genistein maintained intercellular communication in the presence of HGF, indicating that HGF reduces intercellular communication by down regulation of connexin 32 through the c-met/HGF receptor-tyrosine-kinase-mediated pathway. Furthermore, TGF-beta 1 maintained intercellular communication in the presence of HGF. Regulation of intercellular communication in hepatocytes by HGF and TGF-beta 1 might play an important role during liver regeneration.