Effect of EE treatment on plasma clearance of exogenous human t-PA in mice and endogenous, bradykinin-released t-PA in rats. As described in Materials and Methods, mice received injections into a tail vein with 15 μg of recombinant human t-PA (A) or rats received injections into a tail vein with 50 μg/kg body weight bradykinin (B), after pretreatment of the animals with EE or vehicle. Blood samples were collected at the indicated times and t-PA antigen concentrations were determined by ELISA. Data points are the mean ± SD and represent 1 of 3 similar experiments performed in 5-fold (A) and 1 experiment performed in triplicate (B). (○) Vehicle; (•) EE.