Tumor promoters can inhibit gap junction-mediated intercellular communication in cultured cells. The authors evaluated the effects of tumor promoters on intercellular communication between B6C3F1 mouse hepatocytes in primary culture. Intercellular communication between donor and recipient hepatocytes was detected as an increase in autoradiographic grains over recipient cells in contact with donor cells, indicating the passage of labeled nucleotides from donor to recipient hepatocytes. Intercellular communication in untreated and solvent vehicle treated hepatocytes was detected in approximately 80% of the donor-contacting recipients after 8-12 hr culture. Phenobarbital, DDT, Aroclor 1254, lindane, and TPA significantly decreased hepatocyte intercellular communication in a dose-dependent manner. (Copyright (c) 1987 by Academic Press, Inc.)