title: Synovial cell activation. Studies on the mechanism of action of synovial activator activity.
abstract: Synovial activator (SA) from peripheral blood mononuclear cells stimulates the plasminogen activator (PA) levels of human synovial fibroblasts. Using the sensitive technique of transcriptional inhibition followed by a prolonged translation period, data suggested that the first synthesis of mRNA needed for the increase in PA activity began within 40-60 min; this increase in protease activity was reversible on removal of SA from the cultures and also declined after about 3 days even if SA was not withdrawn. The RNA dependent events necessary for the synovial cell activation were to a large extent completed by about 4-8 h while those dependent on protein synthesis lasted for about 12 h. The effectiveness of suboptimal concentrations of SA could be potentiated by all-trans retinoic acid. A similar potentiation was effected by phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine and theophylline, by 8-bromo-cAMP, and by prostaglandins of the E and F series; these last observations suggest cyclic nucleotide involvement in the SA-mediated elevation of synovial fibroblast PA activity.
mesh_terms: D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004357:Drug Synergism; D006801:Humans; D007700:Kinetics; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D015849:Plasminogen Inactivators; D011453:Prostaglandins / Q000494:pharmacology; D013582:Synovial Fluid / Q000378:metabolism; D013583:Synovial Membrane / Q000166:cytology* / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D010726:Phosphodiesterase Inhibitors; D015849:Plasminogen Inactivators; D011453:Prostaglandins; D003609:Dactinomycin; D014212:Tretinoin; D003907:Dexamethasone; D003513:Cycloheximide; D010960:Plasminogen Activators