ABSTRACT
PURPOSE: We performed the present study to investigate whether osteotropic hormomes play roles on the nitric oxide (NO) production in culture of ROS17/2.8 osteoblastic cells. MATERIALS AND METHODS: The osteoblastic cell line ROS17/2.8 cells were cultured in F12 medium supplemented with 5% fetal bovine serum (FBS) at 37 degrees C in a humidified atmosphere of 5% CO2 in air. ROS17/2.8 cells were plated in 96-well plates at a density of 2-3x10 (3) cells/well and grown to confluence. Then the cells were pretreated with osteotropic hormones (parathyroid hormone (PTH) 20-500 ng/mL, 1, 25-dihydroxycholecalciferol (1, 25[OH]2D3) 1-100 nM; prostaglandin E2 (PGE2) 20-500 ng/mL) in the medium supplemented with 0.4% FBS for 72 hours and the cells were treated with cytokines (TNFalpha and IFNgamma) in phenol red-free F12 medium for an additional 48 hours. NO synthesis was assessed by measuring the nitrite anion concentration, the reaction product of NO, in the cell culture medium using Griess reagent. RESULTS: PTH and 1, 25[OH]2D3 pretreatment induced a significant increase in NO production in the presence of TNFalpha and IFNgamma. PGE2 slightly induced NO production compared to the control group. But, PGE2 pretreatment did not affect in NO production in the presence of TNFalpha and IFNgamma. CONCLUSIONS: These results suggest that the actions of osteotropic hormones in bone metabolism may be partially mediated by NO in the presence of cytokines.