Steady-state concentrations and secretion rates of platelet α-granule components are normal in double mutant mice.

(A) Fibrinogen concentrations and secretion from untreated control (−Th) and thrombin (+Th)-treated platelets of mutant and normal mice. After treatment of platelets for 3 minutes with buffer or 1.6 U/mL thrombin, platelets were centrifuged and equivalent proportions of pellets (P) and supernatants (S) were electrophoresed on denaturing gels that were immunoblotted with antifibrinogen antibody. (B) Steady-state levels of PF4 in normal and mutant platelets. Platelet protein (30 μg) was electrophoresed on denaturing gels and immunoblotted with antibody to PF4.