Quantitative electron microscopical autoradiography of calcium during amelogenesis

The 45Ca migration through the stratum intermedium and the secreting ameloblasts towards enamel has been studied with electron microscopical autoradiography in toothgerms of newborn cats. A quantitative procedure was applied to the study of the 45Ca migration in amelogenesis. Two pathways were demonstrated. The relatively more important direct road passed through the stratum intermedium and ameloblast intercellular spaces and reached directly enamel. The second pathway consisted in an intracellular migration through the ameloblast. 45Ca penetrated the cell through its basal pole. The mitochondrias were the most highly labeled organelles at the different experimental time intervals studied. A total absence of silver grains has been noted over the secretory ameloblastic bodies. At 6 hours, the highest labeling was observed over enamel.