Cellular localization and concentration of bone cyclic nucleotides in response to acute PTE administration

The cyclic AMP and cyclic GMP concentrations of alveolar bone of control and PTE-treated cats were measured by chemical and immunohistochemical methods. In the PTE-treated animals, alveolar bone osteoblasts stained intensely for cAMP, but very weakly for cGMP; the periodontal ligament (PDL) cells stained for cAMP similarly to the controls, but some PDL cells stained more intensely for cGMP than their controls; osteocytes stained for cAMP with greater intensity than in the controls; osteoclasts stained intensely for both cyclic nucleotides. We found that bone samples taken from animals 20 and 60 min after administration of PTE contained twice the amount of cAMP, and almost three times the amount of cGMP observed in the controls. These results indicate that the cellular source of bone cyclic nucleotides in PTE-treated animals varies as to cell type, and therefore in bone and PDL the functions mediated by cAMP are not necessarily antagonistic to those mediated by cGMP.