Time course of serum- and bFGF-enhanced TFPI secretion in PASMC. Quiescent PASMC monolayers were treated with basal medium alone (control) or with the basal medium containing serum (10% vol/vol) or bFGF/heparin (10 ng/15 U/mL). At various time points, 50 μL of aliquots was removed from the supernatant conditioned media and stored at −80°C until assayed for TFPI activity. The data shown are the mean of three experiments performed in duplicate ± SD.