Fibrinolysis impairment. (A) The antifibrinolytic activity secreted by aortic rings was evaluated by the ability of electrophoresed proteins to inhibit urokinase-dependent plasminogen activation and fibrin degradation. All the antifibrinolytic activity migrated to a molecular weight of ∼50 kDa corresponding to PAI-1. (B) The antifibrinolytic activity was significantly higher in the l-NAME group (*p < 0.05 versus controls; $p < 0.05 versus l-NAME). (C) The fibrinolytic activity secreted by aortic rings was evaluated by the ability of electrophoresed proteins to activate plasminogen and produce plasmin-induced fibrin degradation. All the fibrinolytic activity migrated to a molecular weight of ∼120 kDa, corresponding to t-PA/PAI-1 complexes. (D) There was no significant difference between the three groups, no free t-PA, and no detectable u-PA. Results are expressed (B,D) in arbitrary units (AU) based on the optical density of gel scan.