title: Timed analysis of the nuclear maturation of oocytes in early preantral mouse follicle culture supplemented with recombinant gonadotropin.
abstract: OBJECTIVE
  To analyze the effects of combined FSH and variable doses of LH on the nuclear maturity and capacity to resume meiosis in oocytes from preantral follicles from prepubertal mice.
  
  
  METHODS
  Prospective, randomized, and controlled in vitro laboratory experiment.
  
  
  METHODS
  Academic research environment.
  
  
  METHODS
  Meiosis was studied after somatic cell removal or after stimulation with hCG plus epidermal growth factor in three culture conditions: maturation medium with FSH alone and with two different doses of LH.
  
  
  METHODS
  The nuclear maturation of the oocytes and the E2, progesterone, and alpha-specific inhibin content of the conditioned medium.
  
  
  RESULTS
  Somatic cell removal and hormonal stimulation were equally effective in inducing germinal vesicle breakdown, but the hormonal stimulus was essential for the completion of meiosis, which was maximal (70%) on day 13 of culture. Continuous addition of LH to FSH during the oocytes' growth made them more prone to spontaneous resumption of meiosis I but resulted in a higher proportion of oocytes reaching the completion of meiosis. Estradiol and progesterone measurements demonstrated that the presence of LH influences luteinization.
  
  
  CONCLUSIONS
  In contrast to oocytes grown in vivo, cumulus cell removal by itself is an insufficient stimulus for oocytes cultured in vitro to complete meiosis. Timed stimulation with hCG and epidermal growth factor increases nuclear maturation rates. A maximum number of metaphase II oocytes are obtained after a 13-day in vitro growth period when LH is added to the maturation medium.
authors.affiliation: Center for Reproductive Medicine, University Hospital and Medical School, Dutch-speaking Brussels Free University, Belgium.
authors.forename: R G
authors.initials: RG
authors.lastname: Cortvrindt
authors.forename: Y
authors.initials: Y
authors.lastname: Hu
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: J E
authors.initials: JE
authors.lastname: Smitz
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002467:Cell Nucleus / Q000502:physiology*; D016922:Cellular Senescence / Q000502:physiology*; D003470:Culture Media; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000494:pharmacology*; D008540:Meiosis / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009865:Oocytes / Q000166:cytology*; D006080:Ovarian Follicle / Q000166:cytology*; D011446:Prospective Studies; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D003470:Culture Media; D011994:Recombinant Proteins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone