GANGLIOSIDES SYNCHRONIZE THE PROTEIN-SYNT HESIS RHYTHM IN HEPATOCYTESIN-VITRO

The kinetics of protein synthesis was studied in the cultures of rat h epatocytes on slides covered with collagen ol fibronectin and kept in a serum-free medium 199 complemented by albumin and insulin. No protei n synthesis rhythm was found in the cultures with markedly separated c ells obtained from a diluted suspension of hepatocytes (''sparse cultu res''). After 0.3-0.4 mu M total gangliosides were added to the medium with such cultures, the rhythm was found in all experiments. Such an effect was earlier found under the influence of a medium conditioned b y a monolayer on the sparse cultures. The results obtained suggest the involvement of gangliosides in synchronization of oscillations of the protein synthesis intensity and call for studies of the conditioned m edium properties.