The Effect of Parathyroid Hormone (1-34) on Cyclic AMP Level, Ornithine Decarboxylase Activity, and Glycosaminoglycan Synthesis of Chondrocytes from Mandibular Condylar Cartilage, Nasal Septal Cartilage, and Spheno-occipital Synchondrosis in Culture

Previously, we reported methods for isolating chondrocytes from the craniofacial complex and their culture in vitro. The response of these chondrocyte cultures to bovine parathyroid hormone (1—34) (PTH) has now been investigated. PTH stimulated glycosaminoglycan (GAG) synthesis, a characteristic of the cartilage phenotype in cultured chondrocytes isolated from mandibular condylar cartilage (MCC), nasal septal cartilage (NSC), and spheno-occipital synchondrosis (SOS). These stimulations of GAG synthesis by PTH were dose-dependent. PTH also increased accumulation of cyclic AMP (cAMP) and the activity of ornithine decarboxylase (ODC), a rate-limiting enzyme in polyamine biosynthesis. However, PTH did not stimulate DNA synthesis. The increases in the cAMP level, ODC activity, and GAG synthesis after addition of PTH (10-⁷ mol/L) were greatest in MCCchondrocytes and least in NSC-chondrocytes. The difference in the responses to PTH of these three types of chondrocytes may reflect differences of the characteristics of these cells in vivo.