Do prostaglandins lead to ovulation in the rabbit by stimulating proteolytic enzyme activity?

• Published in: Fertility and sterility Vol. 55; no. 6; pp. 1183 - 1188
• Main Authors: Miyazaki, Toyohiko, Dharmarajan, Arunasalam M., Atlas, Susan J., Katz, Eugene, Wallach, Edward E.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.06.1991; Elsevier Science
• Subjects: Animals; Biological and medical sciences; Chorionic Gonadotropin - pharmacology; Dinoprost - pharmacology; Endopeptidases - metabolism; Female; Fundamental and applied biological sciences. Psychology; Granulosa Cells - drug effects; Granulosa Cells - ultrastructure; In Vitro Techniques; Indomethacin - pharmacology; Mammalian female genital system; Microscopy, Electron; Microscopy, Electron, Scanning; Morphology. Physiology; Ovarian Follicle - blood supply; Ovarian Follicle - drug effects; Ovarian Follicle - physiology; Ovarian Follicle - ultrastructure; Ovulation - drug effects; Progesterone - blood; Rabbits; Reference Values; Tranexamic Acid - pharmacology; Vertebrates: reproduction; Prostaglandin; Arachidonic acid derivatives; Rabbit; Lagomorpha; Electron microscopy; In vitro; Ovary; Vertebrata; Mammalia; Enzymatic activity; Animal; Female genital system; Physiology; Ovarian follicle
• ISSN: 0015-0282; 1556-5653
• DOI: 10.1016/S0015-0282(16)54372-6

To determine if prostaglandins (PGs) have a direct effect on the ovarian proteolytic enzyme system by examining ultrastructure of the follicle wall and the microvasculature in the presence and absence of indomethacin and by using the isolated perfused rabbit ovary. Nine hours after administration of human chorionic gonadotropin (hCG) or hCG plus indomethacin, follicles were removed and processed for scanning and transmission electron microscopy. Isolated perfused rabbit ovaries were induced to ovulate with PGF2α (100 ng/mL) in the presence and absence of tranexamic acid (0.1, 1.0, or 10 mM), a plasminogen activator inhibitor. The addition of indomethacin to hCG inhibited ovulation and production of PGs without affecting the follicular microvasculature. However, the changes in follicle wall architecture were less pronounced after treatment with indomethacin. Ovulatory efficiency in response to PGF2α (the percent of follicles > 1.5 mm that ovulate) was significantly reduced (P < 0.01) by 10 mM tranexamic acid. These results suggest that PGs induce follicular rupture by activation of proteolytic enzymes located in the follicle wall.