The localization of plasminogen activator in ovulation was investigated using the fibrin slide method. In regular cycle rats, plasminogen activator activity appeared in the external area of the follicle wall (stigma) from 12 hours before ovulation. No activity was noticed in the follicular cavity at this time. A peak of activity was seen at 2 hours before ovulation. After ovulation, the activity decreased markedly. The activity was completely inhibited on fibrin slides to which 10-2M t-AMCHA had been added. No activity was apparent on plasminogen-free fibrin slides.
The plasminogen activator activities on the follicular wall and in the follicular fluid of swine were also measured using the fibrin plate method. The activity on the follicular wall increased from the diestrous to the estrous phase. No activity was apparent in the follicular fluid at any phase.