Connective tissue activating peptide III. Induction of synthesis and secretion of plasminogen activator by synovial fibroblasts.

Connective tissue activating peptide III (CTAP-III) is a platelet factor that induces, in cultured connective tissue cells, activities observed in chronic inflammation. In this study we measured plasminogen activator secretion by synovial fibroblasts after stimulation by CTAP-III. Increased plasminogen activator secretion was observed 24-48 hours after stimulation. Induction was prevented by dexamethasone (10(-9)-10(-7) M), cycloheximide (1 microgram/ml) and, variably, by actinomycin D (0.3 microgram/ml), but not by cytosine arabinoside (10(-4)M). This is the first evidence that CTAP-III induces degradative as well as proliferative activity by connective tissue cells.