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) pl asminogen activator are both enhanced during physical exercise. Whethe r, 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 subm aximal (recreational) exercise, increases in u-PA are mainly due to ch anges in plasma volume, submaximal exercise demonstrates a continuous rise in level of t-PA Ag. During maximal performance peak levels of u- PA and I-PA Ag do not coincide in lime and magnitude, moreover, u-PA A g rather than t-PA Ag is related to t-PA Act. From these results we co nclude that independent mechanisms regulate the exercise-induced plasm a levels of u-PA and t-PA.