Thrombin generation in STAT5-deficient plasma. (A) Expression of clotting factors: mRNA was isolated from control (open) and STAT5-deficient (filled) livers, and quantitative reverse transcription PCR was performed on cDNA. A raw GCN was calculated as described in the Methods, and each GCN was normalized to control mice. STAT5-deficient and control mice had comparable expression of coagulation factors, with the exception of F11 (n = 3, *P = .0069; Student t test). (B) Coagulation factor activity: plasma from control (open) and STAT5-deficient (filled) mice were mixed with the indicated human factor-deficient plasma; factor activities were measured as described in the Methods and normalized to control mice. STAT5-deficient mice had slightly increased FV, FIX, and FX activities, but were comparable to control for all other factor activities (n = 3; *P < .05; Student t test). (C) Thrombin generation: platelet-poor plasma was isolated from STAT5-deficient (- - -) and control mice (—). A fluorogenic thrombin substrate was added to plasma, and fluorescence was measured over time after the addition of TF. STAT5-deficient plasma had comparable endogenous thrombin potential to control mice.