VA Medical Center3

Plasminogen activator (PA) activities were measured in the rat prostatic complex and individual prostatic lobes during early postnatal and pubertal development and in sexually mature adult rats. There was no sign ifi-cant change in PA activity during postnatal prostate development. However, during sexual maturation with puberty, there was a decline in PA activity in the ventral (3-fold), dorsolateral (22-fold), and anterior (19-fold) prostate lobes when activity was expressed per unit protein. A decrease in activity of 25- and 11-fold was found for the dorsolateral and anterior lobes, respectively, when activity was expressed per unit DNA. There was no change in activity in the ventral lobe. The adult ventral prostate (and its secretion) have 3 broad bands of low molecular mass (approximately 23 and 26-32 kDa) plasminogen-independent protease activities. Proteases of these molecular sizes as well as an activity of 1 70 kDa were detected in the dorsolateral prostate. The former proteases in the ventral and dorso-lateral lobes were first found at 21 days of age, whereas the 170 kDa protease was found in dorsolateral prostate immediately post-puberty (48 days). The low molecular mass plasminogen-independent proteases were also able to activate plasininogen (determined by zymography) and hence contribute to the total measured PA activity. Thus, at 21 days of age, the specific activity of plasminogen-dependent protease declined, since the total mea