Deposition of Fluoride, Calcium and Phosphorus in Experimental Low-Phosphorus Rickets

1.Rats were rendered rachitic on a diet adequate in vitamins A and D and in calcium but markedly deficient in phosphorus. Litter-mate rats received the same diet supplemented with Na2HPO4. An equalized intake of fluoride was provided by the drinking water. Ash, fat, fluoride, calcium and phosphorus were determined in femurs, mandibles, molar and incisor teeth.2.The bones of the rachitic rats showed a marked reduction in ash, whereas the teeth were essentially normal. The bones of the rachitic rats also contained less calcium but more phosphorus, resulting in a highly significant reduction in the Ca/P ratio. There was no change in the calcium or phosphorus concentration of the teeth of rachitic rats, nor in the Ca, P or Ca/P ratio in the bones and teeth of the non-rachitic pair-fed and ad libitum-fed rats.3.The femur and mandible ash of the rachitic rats was increased two and one-half times in fluoride content as compared with the bone ash of non-rachitic litter mates. However, markedly less total fluoride was present in the rachitic bones. Fluoride in the teeth was not altered by the rachitic state of the animals.4.The data permitted the conclusion that the observed changes in the rachitic rats were due to the extremely low phosphorus content of the diet rather than to inanition.