Characterization and localization of epidermal growth factor receptors in human developing tooth

In this study the characterization and localization of Epidermal Growth Factor (EGF) receptor in human jaws, from fetuses ranging in age from 9 to 12 weeks is reported for the first time. Binding of [125I]-EGF to membranes obtained from three separate pools of fetal jaws was specific and time- and temperature-dependent. Analysis of the binding data revealed the presence of a single class of binding site with high affinity (Kd, 9.2 x 10(-10) mol/L) and mean binding capacity of 128 fmoles/mg protein. Immunohistochemical study demonstrated the presence of EGF receptors in the early developmental stages of human tooth. In the bud stage, the positivity was localized in the epithelial cells. In the cap stage, EGF receptors was present in the outer and inner enamel cells, in some cells of the stellate reticulum and in the mesenchymal papilla and follicle cells. In the bell stage, positivity for EGF receptors was present in the outer enamel epithelium, in some cells of the stellate reticulum and in the mesenchymal cells of the follicle and papilla. The presence of EGF receptors in the proliferative stages in both epithelial and mesenchymal cells suggests that EGF is involved in the early developmental stages of the human tooth germ.