The role of Akt in GPIb-IX–dependent elevation of platelet cGMP. Washed WT, Akt1^−/−, and Akt2^−/− platelets were stimulated with botrocetin alone or botrocetin (1.5 μg/mL) and vWF (10 μg/mL) in the aggregometer for 8 minutes. The cGMP levels (mean ± SD) in platelets were measured as described in “vWF-induced platelet cGMP elevation.” Data were obtained from 3 tests.