XXXX in osteoblasts.

@entity1 @entity45233 @entity1356 @entity467 @entity33050 @entity1351 @entity461
Active @entity467 has been found in cell extract and medium of @entity1 osteoblast-like cells and MG-63 cells. The released form is stable at neutral and alkaline pH and, in both cell types, intracellular and extracellular @entity467 activities are increased by @entity1356 ( @entity1356 ) and @entity461 ( @entity461 ). To evaluate the physiological role of @entity467 in osteoblasts, we investigated the production and secretion of this enzyme in normal @entity1 synovial fibroblasts and modulation by @entity1356 and @entity461 . Lactate secretion concurrent with release of @entity467 and comparable responses in osteoblasts were also examined. Our data show that synovial fibroblasts respond differently to treatment with the two agents, suggesting a cell-specific regulation of @entity467 and possible involvement in osteoblast physiology. @entity467 involvement was then evaluated in the activation of plasminogen activator (PA) in MG-63 cells using two specific inhibitors of @entity467 , @entity45233 and @entity33050 , in constitutive conditions and after treatment with @entity1356 . As results of PA activity obtained in the presence of IL-beta were in contrast with previous reports, we examined the activities of PA, pro-PA activated with trypsin, and @entity1351 in cell extract and media of MG-63 cells after 24-h treatment with @entity1356 . Results show that in normal conditions and in the presence of @entity1356 , @entity467 is involved in the activation of PA. Moreover, @entity1356 stimulates PA, pro-PA activated by trypsin, and @entity1351 activity in medium, whereas in cell extract it stimulates pro-PA activated by trypsin and @entity1351 activity. @entity1356 has no effect on cell extract-associated PA.
