Radiocalcium Uptake in the Calcified Tissues of Rhesus Monkeys at Various Time Intervals

¹ Harvard School of Dental Medicine, Boston, Massachusetts

The uptake of Ca⁴⁵ in the skeletal and dental tissues of rhesus monkeys was studied at 5-, 27-, 51-, and 168-hour intervals after intravenous Ca⁴⁵ administration. In all the calcified tissues, the uptake was highest in the layer adjacent to its tissue-fluid environment, irrespective of whether this was connective-tissue fluid, serum, or saliva. Decreasing Ca⁴⁵ uptake gradients from the internal dentin and surface enamel toward the dentino-enamel junction and from the subperiosteal and subendosteal layers toward the central layer in both long and flat bones were observed. The uptake in the sutural area of the calvarium was higher than in the adjacent bone. An increasing specific activity ratio from the 5-hour sample to the 168-hour sample was observed in each corresponding layer of the bones and teeth.