[Fluoride levels in plasma and femur after single and multiple administration of fluoride in the rat].

In 12- and 22-week old rats the fluoride levels in plasma and in the femur were studied over a period of 24 hours. Without fluoride administration, the normal fluoride concentration was 0.01 to 0.03 ppm in plasma and an average 50 ppm in the femur. Peak values were observed in the plasma 20 to 40 minutes after fluoride intake, with the peak levels being the same irrespective of the age of the animals and the duration of fluoride administration. A quick and obvious fluoride retention in the femur was registered in young animals. Fluoride elimination from the plasma is influenced by the age of the animals and the previous fluoride load.