Differences in u-PA and t-PA increase during acute exercise: relation with exercise parameters.

Plasma levels of urokinase-type (u-PA Ag) and tissue-type (t-PA Ag) plasminogen activator are both enhanced during physical exercise. Whether, the extent of the increase and the post-exercise clearance rate of the two activators are comparable is not known. We studied the changes in u-PA Ag, t-PA Ag and t-PA activity during a standardized exercise test comprising submaximal and maximal exercise intensity. During submaximal (recreational) exercise, increases in u-PA are mainly due to changes in plasma volume, submaximal exercise demonstrates a continuous rise in level of t-PA Ag. During maximal performance peak levels of u-PA and t-PA Ag do not coincide in time and magnitude, moreover, u-PA Ag rather than t-PA Ag is related to t-PA Act. From these results we conclude that independent mechanisms regulate the exercise-induced plasma levels of u-PA and t-PA.