Fluoride inhibition of DNA synthesis in isolated nuclei from cultured cells

DNA synthesis in isolated nuclei from both fluoride sensitive and resistant LS cells was inhibited by fluoride at and above 3 mM. These fluoride 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 fluoride 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.