Influence of colchicine on the addition of a sugar to the enamel protein in secretory ameloblasts of cultured germs of rat molar tooth by ³H-galactose radioautography

The influence of colchicine on the addition of ³H-galactose to the enamel protein in secretory amelloblasts of cultured germs of rat molar tooth was investigated by light- and electron-microscopic radioautography. In tooth germs cultured without colchicine, the reaction products of ³H-galactose were observed over Golgi cisternae at early chase times and then localized over the enamel with time. In tooth germs cultured with colchicine, the silver grains were seen over the Golgi cisternae, condensing granules and accumulated secretory granules. Some grains also appeared with time over the pale granular material precipitated in the intercellular space with colchicine treatment. In quantitative analysis with light microscopic radioautography, values of silver grain counts over the unit area (100 μm²) on ameloblasts and enamel of colchicine-treated tooth germs were significantly lower at both 0 min and 30 min chase after 30 min pulse than those of control tooth germs, respectively. This finding indicates that colchicine diminished the incorporation of ³H-galactose into the secretory ameloblast of cultured tooth germs. It is suggested that colchicine decreases the activity of the Golgi apparatus with regared to the addition of sugar to the synthesizing glycoprotein in the secretory ameloblast.