Effect of serum urokinase on urine fibrinolytic activity

The purpose of this study was to see if the serum level of urokinase might influence the urine fibrinolytic activity. Serum fibrinolytic activity precipitated in dextran sulfate euglobulin fraction was measured on the plasminogen-rich plate before, during, and after the urokinase infusion. The fibrinolytic activity of euglobulin increased during urokinase infusion by dose-dependent pattern (n = 4, mean: 230%, range: 173-333% of basal level) and decreased below the basal level after cessation of urokinase (n = 4, mean: 18%, range: 0-27% of basal level). There was inverse correlation between the urine fibrinolytic activity and serum fibrinolytic activity in all cases (r = -0.75, 0.01 less than p less than 0.02 in case 2; r = -0.88, 0.0001 less than p less than 0.005 in case 3; r = -0.74, 0.05 less than p less than 0.10 in case 1a and r = 0.59, 0.05 less than p less than 0.10 in case 1b). This finding suggests that the urine fibrinolytic activity production was under control of the serum urokinase level with feedback mechanism.