Stimulation of bone formation and bone resorption by fluoride in thyroparathyroidectomized rats

In sham-operated and TPTX animals, F treatment did not affect final body weight, or serum Ca and P. In sham-treated rats, serum iPTH was not affected by F treatment. At the periosteum, F increased bone formation rate and bone and matrix apposition rates. At the endosteum, F treatment decreased forming surface, bone formation rate, bone and matrix apposition rates, and osteoid maturation rate; and increased endosteal resorbing surface and medullary area. The above-described F effects on bone were observed in TPTX as well as sham-treated animals. The effect of F treatment to stimulate periosteal matrix apposition was enchanced by TPTX. These results indicate that bone changes seen in animals treated with large amounts of F are not due to increased parathyroid activity.