45 rats Wistar, 30 days old, were divided into five groups, receiving different diets: casein, bean and wheat flour. The last two diets were supplemented or not by D-L Methionine and D-L Lysine, respectively. Diets and fluoridated water (25 ppm) were given "ad libitum" for 28 days. After this period of experience, the animals were sacrificed and the mandible and the tibias removed for analyses of fluoride, calcium, phosphorus and ash. The A.A. main conclusions are the following: The fixation of fluorides in bones is significantly increased with the supplement of the limitant factor to dificients diets. In this condition, the mandible shows smaller fixation of fluorides than tibias. The level of calcium, phosphorus and ash shows to be similar in the diferentes groups. This data suggests interaction of the protein quality and the percentual fixation of fluorides, and the necessity of further studies about this problem.
Animals Bone and Bones