标题：Direct Regulation of Bone Resorption of Chick Embryonic Femur in Organ Culture by the Change of Calcium or Phosphate ion Concentration in the Medium
摘要：Bone resorbing activity was determined in organ culture by following the change of biological half life of 45Ca (T1/2) incorporated into bone salts of chick embryonic femur. The elevation of calcium or phosphate ion in the medium brought about an increase of T1/2, indicating that the bone resorption was inhibited. Conversely, the decrease of calcium or phosphate content in the medium resulted in the decrease of T1/2. A change of the magnesium ion concentration in the medium had no discernible effect on T1/2. These results suggest that a direct regulating system exists between bone resorption of chick embryonic femur and calcium or phosphate content in the medium and this phenomenon is specific for calcium or phosphate ion.
