Ovarian smooth muscle and autonomic nerves have been suggested as significant factors in the mechanism of ovulation. Experiments using inhibitors of prostaglandin (PG.) synthesis have indicated that ovarian PCs may also be involved in the ovulatory process. Previous studies have shown that PGF2αenhances and PGE2inhibits ovarian contractility in the rabbit. The present study was conducted to determine the effects of PGE2and PGF2αon human chorionic gonadotropin-induced ovulation in the rabbit. Three groups of 10 rabbits each were utilized: one group served as a control; one group received PGE2: and a third group received PGF2αExperimental solutions were administered via an aortic catheter into the ovarian circulation, beginning 7 hours alter induction of ovulation with human chorionic gonadotropin (HCG) and continuing over the next 4 hours. At 7, 11, 14, and 32 hours after HCG administration, follicles on the ovarian surface were counted and categorized into four stages of development. Administration of PGE2led to a delay in ovulation, while ovaries of PGF2αtreated animals ovulated at the same rate as the controls. The relationship of these results to previous conclusions about prostaglandin effects on the ovarian neuromuscular complex is presented. The role of prostaglandins as intermediates in the ovulatory process is discussed.
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