title: Features of follicle-stimulating hormone-stimulated follicles in a sheep model: keys to elucidate embryo failure in assisted reproductive technique cycles.
abstract: OBJECTIVE
  To evaluate the individual functionality of gonadotropin-stimulated preovulatory follicles, for understanding embryo failure in assisted reproductive technique cycles, in a sheep model.
  
  
  METHODS
  Observational, model study.
  
  
  METHODS
  Public research unit.
  
  
  METHODS
  Fifteen adult Manchega ewes.
  
  
  METHODS
  Synchronization of the estrous cycle with intravaginal progestagens and ovarian stimulation with FSH; evaluation of reproductive activity, plasma sampling, ovarian ultrasonography, and ovariectomies.
  
  
  METHODS
  Determination of estrus behavior, plasma and intrafollicular concentrations of E(2) and inhibin A, number and size of ovarian follicles, and developmental competence of oocytes.
  
  
  RESULTS
  These results support the usefulness of serial measurements of plasma inhibin A for assessment of follicular growth during the FSH treatment, rather than of E(2) assays commonly used. Functionality of FSH-stimulated preovulatory follicles is clearly disturbed, as confirmed by a negative correlation between follicular size and intrafollicular concentrations of inhibin A and E(2) in preovulatory follicles after individual dissection; moreover, the ability of their oocytes to resume meiosis was diminished.
  
  
  CONCLUSIONS
  Functionality of follicles in controlled ovarian stimulation (COS), and developmental competence of their oocytes, is disturbed by the high doses of gonadotropin supplied and finally determined by follicular sizes at starting FSH treatment.
authors.affiliation: Departamento de Reproduccion Animal, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria, Madrid, Spain. aveiga@umich.edu
authors.forename: Almudena
authors.initials: A
authors.lastname: Veiga-Lopez
authors.forename: Veronica
authors.initials: V
authors.lastname: Dominguez
authors.forename: Carlos J H
authors.initials: CJ
authors.lastname: Souza
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Garcia-Garcia
authors.forename: Carmen
authors.initials: C
authors.lastname: Ariznavarreta
authors.forename: Jesus A F
authors.initials: JA
authors.lastname: Tresguerres
authors.forename: Alan S
authors.initials: AS
authors.lastname: McNeilly
authors.forename: Antonio
authors.initials: A
authors.lastname: Gonzalez-Bulnes
mesh_terms: D000465:Algorithms; D000818:Animals; D002452:Cell Count; D048429:Cell Size; D002478:Cells, Cultured; D020964:Embryo Loss / Q000209:etiology*; D047108:Embryonic Development / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D023421:Models, Animal; D006080:Ovarian Follicle / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D011247:Pregnancy; D027724:Reproductive Techniques, Assisted / Q000009:adverse effects*; D012756:Sheep / Q000502:physiology*; D013480:Superovulation / Q000187:drug effects / Q000502:physiology
chemical_list: D004958:Estradiol; D005640:Follicle Stimulating Hormone