INTERCELLULAR COMMUNICATION IN PRIMARY CULTURES OF PUTATIVE PRENEOPLASTIC AND NORMAL HEPATOCYTES

Gap junctional intercellular communication (IC) was studied in gamma-g lutranspeptidase (gamma-GT)-positive and -negative hepatocytes isolate d from carcinogen-treated rats. Putative preneoplastic gamma-GT-positi ve hepatocytes were visualized in monolayer cultures by indirect immun ofluorescence using anti-gamma-GT-antibodies. IC was evaluated by stud ying dye coupling of the cells. Gamma-GT-positive hepatocytes showed a significantly lower dye coupling than did gamma-GT-negative liver cel ls. Spread of the dye Lucifer Yellow CH to neighboring cells was decre ased further by the tumor-promoting chemical phenobarbital in both cel l types in vitro. Also treatment in vivo with the barbiturate signific antly reduced dye coupling of hepatocytes. The findings suggest that a s a result of their decreased ability to communicate, preneoplastic he patocytes may escape from growth control and differentiation signals g iven out by surrounding 'normal' cells.