Levels of lactate dehydrogenase and creatine kinase in plasma of fluoride-treated rabbits.

The effect of different concentrations of fluoride (as sodium fluoride) on the enzymes lactate dehydrogenase (LDH, EC 1.1.1.27) and creatine kinase (CK, EC 2.7.3.2) in rabbit plasma was investigated in vivo and in vitro. Rabbits were dosed orally, for 30 days, with fluoride at 2, 10 or 20 mg per kg body weight as sodium fluoride. LDH and CK levels were determined at 10-day intervals during the treatment. Fluoride, depending on the applied dose, inhibited, had no effect or stimulated the investigated enzymes in vivo. On the other hand, fluoride had no effect on the activity of LDH and CK in vitro.