Serine protease and ovarian paracrine factors in regulation of ovulation.

The controlled target extracellular matrix (ECM) degradation generated by serine protease and regulated by serine protease inhibitor and ovarian paracrine/autocrine factors is an event that affects a wide variety of physiological and pathological processes in the ovary. Evidence cumulated in the past decade clearly showed that the hormone-induced coordinated expression of the tissue-type PA (tPA) produced mainly by granulosa cells and oocyte, and its inhibitor PAI-1 secreted by theca cells in the preovulatory follicles may be responsible for a controlled and directed proteolysis leading to the rupture of selected follicles in the rat, monkey and other mammals. In recent years increasing evidence further demonstrated that oocyte maturation and ovulation may also be modulated by other serine protease and inhibitor, as well as endogenously- produced ovarian paracrine/autocrine factors. Thus, it is important to identify the interrelationship between the serine protease system and the multiple factors, and to know how they regulate the ovarian physiological and pathological processes during oocyte maturation and ovulation.