In-vitro study of cadmium-109 uptake by rat molar enamel during the secretory stage of formation

Abstract

Rat molar explants, taken at an age when enamel formation was entirely in the secretory phase, were cultured for 4 h under conditions previously shown to support enamel-organ viability for 10–12h. The uptake of 109Cd was compared in control explants and their contralateral pairs which had been either stripped of enamel organ, heat-treated, or metabolically inhibited. Evaluation of tracer uptake was by autoradiography, and by quantitatively measuring loss of 109Cd from the medium, and uptake in the explants. The findings indicated that 109Cd was readily absorbed by the forming enamel if the enamel organ was not present. Relative exclusion of the tracer from enamel during the secretory phase was dependent on the integrity and viability of the enamel organ. Binding of cadmium by plasma proteins was not required.