Comparative Fixation of Sr 89 and Ga 45 by Calcified Tissues as Related to Fluoride Induced Changes in Crystallinity

Summary

X-ray diffraction analyses, and Sr⁸⁹ and Ca⁴⁵ uptake studies in tibiae and incisors of control and fluoride treated one-year-old rats were carried out. In the tibia ends and shafts an improvement of bone apatite crystallinity in the direction of the a axis and not the c axis was produced by fluoride ingestion. No changes in incisor apatite crystallinity were observed. Uptake of Ca⁴⁵ and Sr⁸⁹ was decreased in the tibia ends of the 25 and 50 ppm F treated animals. Sr⁸⁹/Ca⁴⁵ ratios in the tibia samples were the same as in the serum specimens. There was a discrimination against Sr in relation to Ca in the incisor bases. Radioactivity in the tibia of one-year-old animals was 1/40 to 1/50 of that found in a group of young animals treated similarly in an earlier experiment. In the young rat the tibia ends were found to incorporate more Sr⁸⁹ and Ca⁴⁵ than the incisor, while the opposite was found in the older rats.