“…VWF is released from EC via either a constitutive or regulated pathway (Loesberg et al, 1983). The latter results from the release of VWF from WPB and occurs rapidly after EC stimulation with secretagogues including thrombin (Loesberg et al, 1983;Levine et al, 1982), the calcium ionophore A23187 (Loesberg et al, 1983), PMA (Loesberg et al, 1983), histamine (Hamilton & Sims, 1987), fibrin (Ribes et al, 1987), complement C5a (Foreman et al, 1994) and C5b-9 (Hattori et al, 1989) and reactive oxygen intermediates (Vischer et al, 1995). An average of only 5% of newly synthesized VWF is sorted into the WPB, while the remainder is constitutively secreted (Sporn et al, 1987).…”