The plasminogen activator activity is markedly increased mainly at the area of the rupture of the follicular wall at the time of ovulation

Abstract

The wall of the follicle in the sow (theca externa, theca interna-membrana granulosa) as well as the follicular fluid showed plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI). The follicular wall exhibited the highest PAA at the time of ovulation. The PAA was much higher at the area of the rupture than in the remaining outstanding part of the follicular wall. In the wall of ruptured follicles, with their openings more or less sealed, the PAA was markedly decreased. In mature follicles, the PAA was higher in theca interna-membrana granulosa than in theca externa. Follicular fluid showed an increasing PAA with the growth of the follicle. In the follicular wall and fluid both types of plasminogen activator, the tissue-type plasminogen activator and the urokinase-type plasminogen activator, were detected with the use of monoclonal antibodies. The PI was lower in theca externa than in theca interna-membrana granulosa of mature follicles, while the PAI was of the same level. In ruptured follicles, the PAI was lower than in mature and growing follicles; the PI showed the opposite pattern. The above findings support the suggestion that PAA plays a significant role in the process of the ovulation.