Effect of Lactation and Calcium Deficiency, and of Fluoride Intake, on Bone Turnover in Rats: Isotopic Measurements of Bone Resorption and Formation

Abstract
The rates of bone formation and resorption were investigated, using isotopic measurements, in calcium-deficient lactating rats and compared to those of calcium-sufficient non-lactating animals. Bone formation was measured by 3H-proline uptake and 3H-hydroxyproline formation, and resorption was measured by the loss of previously incorporated 3H-tetracycline, in whole humerus. The effect of 50 ppm fluoride in the drinking water on both parameters was also examined. The stress of lactation and calcium deficiency significantly increased the rates of bone resorption and formation, but the increase in resorption was greater than in formation which resulted in a net decrease in bone mineral and matrix. Fluoride had no effect on various parameters measured.