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Ovulation as a tissue remodelling process. Proteolysis and cumulus expansion
1Department of Hormone Research, Bernhard Zondek Hormone Research Laboratory, Weizmann Institute of Science, Rehovot, Israel.
Advances in Experimental Medicine and Biology
|January 1, 1995
Summary
Luteinizing hormone (LH) triggers ovulation by stimulating proteolytic enzymes and eicosanoids, which are crucial for follicular rupture and cumulus expansion. Interleukin-1 (IL-1) also plays a key role in mediating these processes for successful ovulation.
Area of Science:
- Reproductive Biology
- Endocrinology
- Molecular Biology
Background:
- Ovulation, essential for mammalian fertilization, is triggered by a luteinizing hormone (LH) surge.
- Key events include cumulus expansion and follicular wall rupture for ovum release.
Purpose of the Study:
- To elucidate the biological components of the ovulatory response, focusing on follicular rupture and cumulus maturation.
- To investigate the roles of proteolytic cascades, eicosanoids, and interleukin-1 in ovulation.
Main Methods:
- Examined the effects of LH/hCG on proteolytic enzymes (PA, plasmin, MMPs) and eicosanoid production.
- Utilized enzyme inhibitors (indomethacin, NDGA, MK-886) and an IL-1 receptor antagonist (IL-1ra).
- Performed zymographic analysis to assess collagenolytic activity in ovarian extracts.
Main Results:
- LH/hCG stimulates proteolytic enzymes that degrade follicular matrix and collagen, essential for rupture.
- Eicosanoids (prostaglandins, leukotrienes) mediate LH-stimulated follicular collagenase activity.
- Interleukin-1 (IL-1) inhibits cumulus expansion and detachment, suggesting a role in mediating gonadotropin action.
Conclusions:
- Proteolytic enzymes and eicosanoids are critical mediators of LH-induced follicular rupture.
- Interleukin-1 (IL-1) is implicated in facilitating gonadotropin action on cumulus expansion, a key step in ovulation.