Alteration of murine odontogenic patterning and prolongation of expression of epidermal growth factor mRNA by retinol in vitro.
Retinoids alter the patterning of murine odontogenesis in vivo and stimulate epithelial proliferation. Because odontogenesis is dependent on proliferation of mandibular epithelium, the effects of retinol on the patterning of odontogenic epithelium were studied. These experiments control for developmental stage, applied retinoid concentration and duration of exposure. Explants exposed for 24 h to 0.1 micrograms/ml of retinol exhibited enhanced odontogenesis. Day-9 mandibles exposed to retinol at 1-5 micrograms/ml had altered epithelial patterns consistent with those in previous in vivo experiments, including supernumerary epithelial buds in regions associated with supernumerary incisors in vivo. These changes were associated with a dose-dependent increase in epithelial proliferation and a prolonged expression of epidermal growth factor (EGF) mRNA. Altered expression of EGF mRNA may be responsible for the disrupted pattern of the dental lamina. This is the first report of a retinoid-induced alteration in EGF mRNA expression.
Kronmiller
J E
JE
Department of Biostructure and Function, School of Dental Medicine, University of Connecticut Health Center, Farmington 06032.
Upholt
W B
WB
Kollar
E J
EJ
D000818:Animals; D001934:Branchial Region; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000032:analysis; D004815:Epidermal Growth Factor / Q000032:analysis / Q000187:drug effects* / Q000235:genetics; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects; D005784:Gene Amplification; D008334:Mandible; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008940:Mitotic Index / Q000187:drug effects; D009805:Odontogenesis / Q000187:drug effects* / Q000235:genetics; D009924:Organ Culture Techniques; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects*; D014083:Tooth Germ / Q000166:cytology / Q000187:drug effects; D014158:Transcription, Genetic; D014801:Vitamin A / Q000494:pharmacology*
D012333:RNA, Messenger; D014801:Vitamin A; D004815:Epidermal Growth Factor; D004247:DNA