In vitro study of cellular influence on 45Ca uptake in developing rat enamel.

The in vitro method for culture of molar teeth from eight-day-old rats, as reported in this study, appeared to sustain reasonably normal activity in the cells of the enamel organ and pulp through culture periods of four to eight hours. Inhibition of metabolic activity in the explants by addition of 5 mM iodoacetate or 2,4-dinitrophenol to the culture medium, or by heating at 70 C for 10 minutes, did not appear to affect the intensity or pattern of 45Ca uptake in the more advanced, rapidly mineralizing areas of the enamel. Neither did stripping of the enamel organ from the surface of the enamel have a demonstrable effect in those areas. However, metabolic inhibition with 2,4-dinitrophenol, heat killing or stripping of the enamel organ resulted in increased 45Ca uptake in newly formed enamel adjacent to the secreting ameloblasts. It is hypothesized that calcium flux into newly formed enamel matrix is controlled, in part, by movement of the calcium, which diffuses between the ameloblasts toward the enamel surface, away from the enamel through the ameloblasts.