title: Human ovarian steroid secretion in vivo: effects of GnRH agonist versus antagonist (cetrorelix).
abstract: BACKGROUND
  In order to investigate whether gonadotrophin-releasing hormone (GnRH) antagonists exert a significant effect on steroid secretion in vivo compared with GnRH agonists, concentrations of sex steroid hormones (oestradiol, progesterone and testosterone) were studied in follicular fluid from women undergoing ovarian stimulation and treated with either GnRH agonist or antagonist. In addition, the correlation between follicular fluid steroid hormone concentrations and variables of follicular and oocyte development was evaluated.
  
  
  METHODS
  Microparticle enzyme immunoassay and radioimmunoassays were used.
  
  
  RESULTS
  The mean (SEM) follicular fluid oestradiol concentration was significantly lower in patients treated with GnRH antagonist than in those treated with GnRH agonist (542.0 +/- 76.9 versus 873.0 +/- 105.1 pg/ml, P = 0.02), which correlates with the mean serum oestradiol concentrations found in these two groups. No significant differences were found between groups in follicular fluid progesterone concentrations. Women undergoing GnRH antagonist treatment showed similar concentrations of follicular fluid testosterone compared with GnRH agonist-treated women (14.8 +/- 1.1 versus 13.3 +/- 2.7 ng/ml). The oestradiol:testosterone ratio was markedly reduced in women treated with GnRH antagonist (49.1 +/- 2.3 versus 60.1 +/- 4.4, P = 0.04). In contrast, no differences were found either in the progesterone:testosterone ratio, or in the oestradiol:progesterone ratio.
  
  
  CONCLUSIONS
  GnRH antagonist therapy in women undergoing ovarian stimulation had a significant effect on ovarian follicular steroidogenesis.
authors.affiliation: IVI-Madrid, Madrid, Spain. jgvelasco@ivi.es
authors.forename: J A
authors.initials: JA
authors.lastname: Garcia-Velasco
authors.forename: V
authors.initials: V
authors.lastname: Isaza
authors.forename: C
authors.initials: C
authors.lastname: Vidal
authors.forename: A
authors.initials: A
authors.lastname: Landazábal
authors.forename: J
authors.initials: J
authors.lastname: Remohí
authors.forename: C
authors.initials: C
authors.lastname: Simón
authors.forename: A
authors.initials: A
authors.lastname: Pellicer
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004958:Estradiol / Q000032:analysis / Q000378:metabolism; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage; D015571:Follicular Fluid / Q000737:chemistry; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists* / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D007124:Immunoenzyme Techniques; D016729:Leuprolide / Q000008:administration & dosage; D010053:Ovary / Q000187:drug effects* / Q000378:metabolism*; D010062:Ovulation Induction; D011374:Progesterone / Q000032:analysis / Q000378:metabolism; D011863:Radioimmunoassay; D011994:Recombinant Proteins / Q000008:administration & dosage; D020554:Sperm Injections, Intracytoplasmic; D013739:Testosterone / Q000032:analysis / Q000378:metabolism
chemical_list: D006063:Chorionic Gonadotropin; D012739:Gonadal Steroid Hormones; D011994:Recombinant Proteins; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D005640:Follicle Stimulating Hormone; D016729:Leuprolide; C062876:cetrorelix