RATE OF REMOVAL OF COLLAGEN AND MINERAL FROM BONE AND CARTILAGE

The quantitative relationship between collagen and mineral dynamics in bone and costal cartilage has been studied. Young rats were injected simultaneously with both 14C-proline and 85Sr. The animals were sacrificed at intervals ranging from 1-20 days after injection. The femurs, proximal 20 per cent of the tibias, and the entire costal cartilage were removed for analyses. Hydroxyproline was isolated from the tissues, and the specific activity of both the 14C-hydroxyproline and the 85Sr-mineral were determined. The results show that in both the proximal end of the tibia and the femur, the rates of removal of the collagen and mineral phases are identical. However, in the costal cartilage the rate of removal of collagen was markedly less than that in bone, while the rate of removal of the mineral was similar to that found in bone. In costal cartilage, therefore, the rates of removal of the collagen and mineral were not identical. © 1969.