The effect of high fluoride intake on tissue trace elements and histology of testicular tubules in the rat.

1. Male Wistar rats were exposed to fluoride (F) at concentrations of 100- and 200 ppm in their drinking water for 6- and 16 weeks. 2. The high F intake caused several-fold increase in the F concentrations in the testes and bone as compared with control rats, both after the 6- and 16 wk exposure; the bone F, but not testicular F, appeared to increase with dose and time. 3. F exposure (100- and 200 ppm) decreased significantly the concentrations of zinc (Zn) in the testes, plasma, liver and kidneys particularly in the 16 wk groups; in the bone Zn tended to increase, however. 4. The iron concentrations of the testes and plasma were not affected by F, whereas those of the liver, kidneys and bone appeared to increase under the influence of F. 5. The concentrations of copper and manganese in the testes, liver and kidneys were not changed by F exposure. 6. Fifty percent of the 100- and 200 ppm F rats after 16 weeks exhibited histopathologic changes in the germinal epithelium of the testes, which resembled those in Zn-deficient rats. 7. The data suggest that a deprivation of testicular Zn due to a high F intake may be directly responsible for the injury of testicular tubules.