When fluoride is administered to a living body, a considerable amount is promptly absorbed, resulting in a rise in the serum fluoride concentration. This study discusses the changes in the serum total fluoride concentration and ionic fluoride concentration , as well as in the serum calcium concentration in Japanese white rabbits after fluoride administration by intubation. Rabbits were given an NaF solution containing 1 , 2, 4, 6, 8 or 10 mgF/kg body weight. Blood was then taken from a marginal vein and tested. After fluoride intubation, the ionic fluoride concentration and the total fluoride concentration both rose promptly. Furthermore, the greater the fluoride dose, the more rapid the rise in serum ionic fluoride concentration and total fluoride concentration. For all fluoride treated groups, the rises in serum ionic fluoride concentration and total fluoride concentration 4 hours after administration were significantly higher than before administration. The serum ionic Calcium concentration was decreased 4 hours after fluoride administration, but later returned to normal levels (same as before administration) at 24 hours after administration. There was no significant difference in the serum total calcium concentration in all fluoride treated groups before and after fluoride administration. Serum phophorus concentration in the fluoride treated groups reached its lowest value 15 or 30 minutes after fluoride administration, but then soon returned to pre-administration values. The phosphorus concentrations at each time after administration were not significantly different from those before administration. On the other hand, blood sugar values determined within 4 hours after administration were significantly higher than those before fluoride administration. In all treated groups, however, blood sugar decreased as time passed after administration and eventually drew near to that of pre-administration values. The half-life of serum fluoride after administration was determined from the ionic fluoride concentration and total fluoride concentration. The half-life of every concentration increase proportionately to the increase in the fluoride dose.
