title: Parathyroid hormone stimulation of the Na+/K+ pump in rat clonal osteosarcoma cells.
abstract: A clonal line of osteoblastic cells from a rat osteogenic sarcoma (UMR 106-06), known to possess parathyroid hormone (PTH)-responsive adenylate cyclase, has been shown to increase its rate of K+ uptake mediated by a Na+/K+ pump after exposure to the hormone. The increase in pump activity was not associated with significant changes in K+ efflux or Na+ influx and would therefore be expected to alter intracellular levels of both Na+ and K+. The maximal (75%) increase in pump activity was noted at a PTH concentration of 100 micrograms/l and half-maximal stimulation at 1.9 micrograms/l. The effect appeared to be independent of the adenylate cyclase system, since a synthetic peptide antagonist of PTH activation of adenylate cyclase failed to prevent stimulation of the Na+/K+ pump. Similarly, prostaglandin E2, an alternative agonist of adenylate cyclase in these cells, had no effect on the Na+/K+ pump. This novel action of PTH on monovalent cation transport in osteoblast-like cells should provide a clearer insight into the mechanisms of hormone-induced bone resorption.
mesh_terms: D000818:Animals; D002460:Cell Line; D002999:Clone Cells; D007473:Ion Channels / Q000187:drug effects*; D010006:Osteoblasts / Q000187:drug effects*; D012516:Osteosarcoma / Q000473:pathology; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013268:Stimulation, Chemical; D019379:Teriparatide
chemical_list: D007473:Ion Channels; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D019379:Teriparatide; D012964:Sodium; D011188:Potassium