Parathyroid hormone (PTH) strongly stimulates hyaluronan (HA) synthesis and secretion of both normal and carcinogenic cells of the osteoblastic lineage and improves skeletal microarchitecture. HA, a glycosaminoglycan component of the extracellular matrix (ECM), is capable of transmitting ECM-derived signals to regulate cellular function. In this study, we investigated whether the changes of HA metabolism induced by PTH (1-34) and PTH (7-84) peptides in moderately MG-63 and well-differentiated Saos 2 osteosarcoma cell lines, are correlated to their migration capabilities. Our results demonstrate that intermittent PTH (1-34) treatment significantly (P < or = 0.01) supported the migration of MG-63 cells, increased their HA-synthase-2 (HAS2) expression (P < or = 0.001), and enhanced their high-molecular size HA deposition in the pericellular matrix. Both increased endogenous HA production (P < or = 0.01) and treatment with exogenous high-molecular weight HA (P < or = 0.05) correlated to a significant increase of MG-63 cell migration capacity. Transfection with siHAS2 showed that PTH (1-34), mainly through HAS2, enhanced HA and regulated MG-63 cell motility. Interestingly, continuous PTH (1-34) treatment stimulated both Saos 2 cell HAS2 (P < or = 0.001) and HAS1 (P < or = 0.001) isoform expression inhibited their HYAL2 expression (P < or = 0.001) and modestly (P < or = 0.05) enhanced their migration. Therefore, the PTH (1-34) administration mode appears to distinctly modulate the migratory responses of the MG-63 moderately and Saos 2 well-differentiated osteosarcoma cell lines. Conclusively, the obtained data suggest that there is a regulatory effect of PTH (1-34), in an administration mode-dependent manner, on HA metabolism that is essential for osteosarcoma cell migration.