Summary
We determined the plasma levels of tissue plasminogen activator (t-PA), plasminogen
activator inhibitor (PAI) activity and their antigen levels including urokinase plasminogen
activator (u-PA) in 33 male and 27 female normal subjects. Males had mean t-PA activity
of 0.50 iu/ml which was significantly lower (p <0.01) than the females 0.64 iu/ml. Males had higher (p <0.001) mean PAI activity (15.5 AU/ml) as compared to females 10.3 AU/ml. The respective
mean levels of t-PA and PAI antigen were significantly higher (p <0.01) in males (8.1 ng/ml and 17.6 ng/ml) than in females (6.2 ng/ml and 12.1 ng/ml).
The mean u-PA level in males was 1.54 ng/ml which was significantly higher (p <0.01) than in females with 1.02 ng/ml. In post-venous occlusion studies, females
had a greater mean response of 8.6 fold in t-PA activity as compared to males with
a mean of 4.5 fold increase. The mean t-PA antigen response in males was 2.0 fold
increase as compared to 2.6 fold increase in the females. No significant responses
were seen in both sexes in either PAI activity or antigen levels when compared with
the resting state. In zymography studies, free t-PA, its inhibitor complexes and u-PA
were demonstrated in the euglobulin fractions of stored plasma. This study demonstrates
that significant differences in t-PA, u-PA and PAI exist between male and female subjects
which should be taken into account when determining their levels in clinical conditions.
