title: Effects of a GnRH agonist on oocyte number and maturation in mice superovulated with eCG and hCG.
abstract: The objective was to investigate the effects of a gonadotropin-releasing hormone agonist (GnRH) on ovulation rate and the number and maturation of oocytes in mice superovulated with equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). Thirty 3-month-old BALB/C female mice (weight: 25-30 g) were assigned to three experimental groups: control, superovulated, and superovulated with GnRH pretreatment (n=10 per group). Control mice received an i.p. injection of 0.1 ml physiological saline solution. Superovulation was induced with 5 IU eCG (i.p.) and 5 IU hCG 48 h later. Mice in the superovulated with GnRH pretreatment group were given GnRH (20 mg/kg Fertirelin, i.m.), 24 h before superovulation. Thirteen hours after hCG administration, mice were sacrificed by cervical dislocation and blood samples were collected to determine serum progesterone concentration (by radioimmunoassay). Ovaries and oviducts were also harvested to enumerate corpora lutea and cumulus-enclosed oocytes. Progesterone concentrations were not significantly different among groups. The oocyte number and the maturation, ovulation rate, and the number of corpora lutea were higher in GnRH-treated mice than both controls and superovulated mice. In conclusion, GnRH given 24 h before superovulation with eCG-hCG increased the number and maturation of oocytes and the rate of ovulation in mice.
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, Yuzuncu Yil University, 65080, Kampus, Van, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kanter
authors.forename: Cengiz
authors.initials: C
authors.lastname: Yildiz
authors.forename: Ismail
authors.initials: I
authors.lastname: Meral
authors.forename: Ahmet
authors.initials: A
authors.lastname: Koc
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Tasal
mesh_terms: D000818:Animals; D002452:Cell Count; D006063:Chorionic Gonadotropin / Q000008:administration & dosage*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage* / Q000819:agonists / Q000031:analogs & derivatives*; D006064:Gonadotropins, Equine / Q000008:administration & dosage*; D051379:Mice; D008807:Mice, Inbred BALB C; D009865:Oocytes / Q000166:cytology* / Q000254:growth & development*; D011374:Progesterone / Q000097:blood; D013480:Superovulation
chemical_list: D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; C009936:fertirelin