title: Effect of cyclic 3', 5' adenosin-monophosphate on osteogenesis embryonic bone cultivated in tissue culture: an autoradiographic study.
abstract: The aim of this study was to evaluate the effect of cyclic 3', 5' adenosin-monophosphate (cAMP) on DNA synthesis of embryonic alveolar bone in tissue culture.
  
  
  METHODS
  Bone fragments were cultured in the medium composed of 80% medium 199, 15% horse serum, 4 mg/ml glucose, 100 microg/ml penicillin using the grid method. The explants were cultured up to 12 days. In the second series, the effect of cAMP in a concentration of 10(-6)M on bone during 12 days was studied. DNA synthesis was determined by calculating mitotic labelling indices for (3)H-thymidine incorporation into cells within cultured explants at 3 to 12 days. The medium was supplemented with 1 microCurie/ml (3)H-thymidine for 4 hours and processed for autoradiography. The mitotic labelling index was determined in the histological sections. All values wer presented as mean+/-standard deviation. Statistical significance was defined by p-values of 0.05 or less.
  
  
  RESULTS
  Morphological and statistical analysis showed that there were differences in mitotic incidence (MI) and silver grain densities over osteoblasts in control cultures and with cAMP. The mean value of MI was 4,627+/-1,001 in control and 7,706+/-1,188 in the cultures where cAMP was added (p<0.05).
  
  
  CONCLUSIONS
  Thus cAMP inhibited bone resorption and stimulated new bone formation in tissue culture. This study provides a novel concept that may help to identify new therapeutic targets.
authors.affiliation: Department of Stomatology, Tartu University Hospital, 8 Puusepa str., Tartu 51014, Estonia. Edvitar.Leibur@kliinikum.ee
authors.forename: Edvitar
authors.initials: E
authors.lastname: Leibur
authors.forename: Elbi
authors.initials: E
authors.lastname: Lepp
mesh_terms: D000539:Alveolar Process / Q000187:drug effects* / Q000196:embryology; D000818:Animals; D001345:Autoradiography; D001857:Bone Matrix / Q000187:drug effects; D001862:Bone Resorption / Q000503:physiopathology; D002113:Calcification, Physiologic / Q000187:drug effects; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D003470:Culture Media; D000242:Cyclic AMP / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D051379:Mice; D008940:Mitotic Index; D010006:Osteoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D019275:Radiopharmaceuticals; D013936:Thymidine / Q000378:metabolism; D046509:Tissue Culture Techniques; D014316:Tritium
chemical_list: D003470:Culture Media; D019275:Radiopharmaceuticals; D014316:Tritium; D004247:DNA; D000242:Cyclic AMP; D013936:Thymidine