Reduced Fluoride Sensitivity of Liver Cells from Rats Chronically Exposed to Fluoride

: The fluoride sensitivity, determined as effect on protein synthesis (incorporation of 14C‐leucine), of liver and kidney cells in suspension culture was explored. The cells were freshly prepared by collagenase perfusion from rats given drinking water with or without addition of 100 p.p.m. (5.26 mM) fluoride for 9–28 weeks. The fluoride sensitivity of the liver cells from rats given fluoridated water for more than 9 weeks was decreased compared to cells from control rats, whereas the fluoride sensitivity of the kidney cells from fluoride exposed and control rats appeared similar. Fluoride resistance (i.e. decreased sensitivity) may thus develop also in cells in vivo. When exposed to 3 mM NaF for 1 hour the intracellular concentration of fluoride in liver cells from fluoride exposed and control animals was similar.