Endocrine Abstracts

During each reproductive cycle, the ovary produces fertilizable ova in a cyclic manner. This involves growth and development of premature follicles as well as the maturation of oocytes to mature ova. The process culminates in the rupture of the follicular wall and the extrusion of the mature ovum into the periovarian space. After ovulation, a corpus luteum (CL) is formed from the remnants of an ovulated follicle. Follicular development, ovulation, formation and regression of CL as well as follicular atresia are processes characterized by dramatic tissue remodeling and angiogenesis that require controlled and targeted proteolysis.

Correlative data implicate that members of the plasminogen activator (PA-) and matrix metalloproteinase (MMP-) systems may be involved in several of the proteolytic events that take place in the ovary. These two proteolytic systems, comprise both proteinases and associated inhibitors, that are thought to act in concert via a cascade of proteolytic events, the end result of which is the generation of a broad spectrum proteolytic activity, that can mediate physiological tissue remodeling throughout the body.

Recent studies with protease deficient mice have also provided new insights into the functional role of proteases in many biological processes. However, the few functional studies using protease deficient mice so far performed have not provided detailed information on the functional role of individual proteases in female reproduction or identified a protease with a definite role in reproduction. At present it can therefore not be excluded that follicular wall rupture and other ECM remodeling processes in the ovary to a large extent is the result of yet unknown proteases.

This lecture highlights the key features of the PA- and MMP-systems and focuses on their regulation and functional role in the ovulatory mechanism and other ECM remodeling processes that takes place in the ovary during each reproductive cycle.