ATP-induced vWF release: Effect of adenosine removal by ADA. Confluent HUVECs were incubated with ADA (1 U/mL) ± 2-chloro-adenosine (2Cl, 10 μmol/L) as indicated; 3 minutes later, 100 μmol/L ATP was added where indicated, and the incubation continued for 30 minutes at 37°C. The experiment was performed in the absence or presence of 100 μmol/L IBMX. Data are the mean ± SEM of 5 to 8 experiments. *P < .05.