Abstract
DNA synthesis in isolated nuclei from both F- sensitive and resistant LS [mouse fibroblast] cells was inhibited by F- at and above 3 mM. These F- concentrations also had an inhibitory effect on DNA synthesis in intact sensitive cells, but not in resistant cells. Due to previous findings that the intracellular F- concentration in the sensitive cells is only 30-40% of the extracellular, it is suggested that inhibition of DNA synthesis in intact cells is secondary to the inhibitory effect on protein synthesis.