[Effect of gonadotropin releasing hormone agonist (Gn-RHa) on steroidogenesis in human and rat ovaries].
The effects of Gn-RHa on rat granulosa cells and on human granulosa and luteal cells were examined. (I) In rat granulosa cells: 1) Gn-RHa inhibited the stimulating effect of PMSG on progesterone and estradiol production. 2) In a tracer experiment, Gn-RHa inhibited PMSG-stimulated progesterone production by stimulating 20 alpha-hydroxyprogesterone production. On the other hand, Gn-RHa inhibited estradiol production by inhibiting PMSG-stimulated aromatization. 3) On 20 alpha-hydroxysteroid dehydrogenase activity, it appears that Gn-RHa accelerates the maximum velocity and decreases the affinity of the enzyme to 20 alpha-hydroxyprogesterone as the substrate. (II) In man: 1) In granulosa cells during the ovulatory phase, Gn-RHa inhibited PMSG-stimulated progesterone and estradiol production. 2) In luteal cells, Gn-RHa inhibited hCG-stimulated progesterone production. 3) The affinity of Gn-RH receptor in the corpus luteum was lower than that in rat ovaries. These results suggest that in the human ovary as well as in the rat ovary, Gn-RHa might have a direct effect on the development of the follicle.
Kimura
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Department of Obstetrics and Gynecology, Yokohama City University School of Medicine.
D000818:Animals; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000037:antagonists & inhibitors; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006064:Gonadotropins, Equine / Q000037:antagonists & inhibitors; D006107:Granulosa Cells / Q000378:metabolism; D006801:Humans; D008184:Luteal Cells / Q000378:metabolism; D010053:Ovary / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol