Abstract
Parathyroid hormone (PTH) and calcitonin (CT) are known to affect not only bone tissue but also dentine tissue. In the mechanism of action of these hormones on bone tissue, involvement of adenylate cyclase-cAMP system has been reported. However, studies of the mechanism of these hormones on dentine tissue remain insufficient. In the present study, using TCA extraction and double antibody RIA, the content of cAMP in dentine pulp tissue was shown to be much higher than that in the serum. Using dental pulp cells obtained from rabbits of 600 g body weight and cultured for 4 days, which abounded in odontoblasts, cAMP levels in the culture media after 30 minutes' contact with hormones were examined. PTH, at 0.01-1.0μM, increased cAMP levels significantly in a concentration-dependent manner. CT and Parotin, on the other hand, did not influence cAMP levels when added separately. However, when PTH (1 μ M) and CT (10μM) were added together, the increase of extracellular cAMP caused by PTH was inhibited by about 50%, indicating a possible interaction of these hormones in the signal transduction in the odontoblasts.
