title: Direct effect of gonadotropin-releasing hormone agonists on the rabbit ovarian follicle.
abstract: OBJECTIVE
  To determine if gonadotropin-releasing hormone agonist (GnRH-a)-induced oocyte maturation and degeneration can be attributed to the direct actions on the follicle.
  
  
  METHODS
  Mature rabbit follicle culture.
  
  
  METHODS
  The mature follicles were cultured with human chorionic gonadotropin (hCG) (100 ng/mL), buserelin acetate (10(-9) to 10(-6) M), leuprolide acetate (10(-9) to 10(-6) M), or buserelin acetate (10(-7) M) with a GnRH antagonist (10(-8) to 10(-6) M) for 14 hours.
  
  
  METHODS
  The percentage of oocytes achieving germinal vesicle breakdown, the oocyte degeneration rate, prostaglandins (PG) production by mature follicles, and the frequency of fertilization and embryonic development.
  
  
  RESULTS
  Gonadotropin-releasing hormone agonist induced the meiotic maturation of follicle-enclosed oocytes in a dose-dependent manner while concomitantly increasing oocyte degeneration. The simultaneous addition of GnRH antagonist inhibited significantly GnRH-a-induced oocyte maturation and PG production by the mature follicles. Furthermore, a GnRH antagonist reversed the oocyte degeneration rate that had been increased by GnRH-a. The rates of normal fertilization and early embryonic development were significantly reduced in the oocytes matured by GnRH-a as compared with those matured by hCG.
  
  
  CONCLUSIONS
  Gonadotropin-releasing hormone agonist acts directly on mature rabbit follicles to trigger the oocytes to undergo meiotic maturation, but oocytes matured in vitro by GnRH-a are not necessarily cytoplasmically mature.
authors.affiliation: Department of Obstetrics and Gynecology, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Ando
authors.forename: S
authors.initials: S
authors.lastname: Shiokawa
authors.forename: N
authors.initials: N
authors.lastname: Koyama
authors.forename: T
authors.initials: T
authors.lastname: Nanno
mesh_terms: D000818:Animals; D002064:Buserelin / Q000494:pharmacology*; D016922:Cellular Senescence / Q000187:drug effects; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005307:Fertilization in Vitro; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000502:physiology*; D016729:Leuprolide / Q000494:pharmacology*; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism; D011453:Prostaglandins / Q000378:metabolism; D011817:Rabbits
chemical_list: D006063:Chorionic Gonadotropin; D011453:Prostaglandins; D007987:Gonadotropin-Releasing Hormone; D016729:Leuprolide; D002064:Buserelin