Objective:To explore the anabolic effect of intermittently adminstrated PTH on rat osteoblast cells(ROBs). Methods:The ROBs divided into two groups:①Control(Ctr),the cells were cultured without PTH in an incubation cycle(24 h);②Intermittent expoure to PTH(Itm), the cells were cultured with PTH at the first 6 h,but without PTH at the subsequent 18 h. Cellular proteins at 24 h were disolved and seperated in two-dimensional gel electrophoresis(2-DE). Two of the dramatically upregulated proteins were detected by matrix assisted laser desorption/ionization time-of-flight mass spectrometry(MADI-TOF-MS). Results:The two upregulated proteins were β-actin and vimentin. Both of them were cytoskeletal proteins. Conclusion:β-actin and vimentin may play a role in the anabolic effect of intermittent PTH on rat osteoblast cells.