Roles of Kidney and Skeleton in Regulation of Body Fluid Fluoride Concentrations 1

Summary

An acute dose of 2.94 mg of fluoride, given by gastric intubation to mature female rats with or without previous high fluoride intakes, was rapidly absorbed and distributed in the body fluid compartments. Limited excursions of plasma fluoride contents were observed since the mechanisms establishing equilibrium of distribution of fluoride between blood and bone and those of urinary excretion of fluoride functioned rapidly. There was no evidence that animals with initially elevated skeletal fluoride contents were deficient in ability to control elevations of plasma fluoride contents or to dispose of fluoride in the urine. Results from the animals with a previous low fluoride exposure showed that skeletal regulation of the body fluoride was faster and quantitatively larger than excretion of fluoride by the kidney. At least 29% of the fluoride administered was absorbed by these animals in 5 hr. At 50 hr at least 88% of the administered dose was absorbed and 70% of the dose had been deposited in the skeletons.