title: Growth and differentiation factor 9 promotes oocyte growth at the primary but not the early secondary stage in three-dimensional follicle culture.
abstract: OBJECTIVE
  Factors that differentially regulate oocyte and granulosa cell growth within the early preantral follicle and how these factors differ at each stage of follicle growth remain poorly understood. The aim of this study was to isolate and evaluate the effect of recombinant growth and differentiation factor 9 (GDF9) on oocyte and granulosa cell growth at the primary and early secondary stages of preantral follicle growth during in vitro culture.
  
  
  METHODS
  Primary stage follicles (diameters of 50-89 μm) and early secondary stage follicles (diameters of 90-120 μm) were isolated from immature mice, and individual, intact follicles were cultured in vitro in the presence and absence of recombinant GDF9. The effects of GDF9 on follicle growth were determined by the assessment of changes in the follicle volume during culture. The growth of the granulosa cell and oocyte compartments of the follicles was evaluated separately at each stage.
  
  
  RESULTS
  GDF9 significantly increased the growth of isolated follicles at both the primary and early secondary follicle stages. Independent evaluation of the granulosa cell and oocyte compartments revealed that, while GDF9 promoted granulosa cell growth at both stages of folliculogenesis, oocyte growth was stage specific. GDF9 promoted growth of the oocyte at the primary, but not the early secondary, follicle stage.
  
  
  CONCLUSIONS
  These findings demonstrate a stage-specific role for GDF9 in the regulation of oocyte and granulosa cell growth at the primary and early secondary stages of preantral follicle development.
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92093-0633, USA. hcookandersen@ucsd.edu.
authors.forename: Heidi
authors.initials: H
authors.lastname: Cook-Andersen
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92093-0633, USA.
authors.forename: Kirsten J
authors.initials: KJ
authors.lastname: Curnow
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92093-0633, USA.
authors.forename: H Irene
authors.initials: HI
authors.lastname: Su
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92093-0633, USA.
authors.forename: R Jeffrey
authors.initials: RJ
authors.lastname: Chang
authors.affiliation: Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, 92093-0633, USA. sshimasaki@ucsd.edu.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Shimasaki
mesh_terms: D000818:Animals; D005260:Female; D006107:Granulosa Cells / Q000166:cytology / Q000378:metabolism*; D055429:Growth Differentiation Factor 9 / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009865:Oocytes / Q000166:cytology / Q000254:growth & development*; D009866:Oogenesis / Q000187:drug effects* / Q000502:physiology; D009924:Organ Culture Techniques; D006080:Ovarian Follicle / Q000166:cytology / Q000254:growth & development*
chemical_list: C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9
keywords: GDF9; Granulosa cell; Growth and differentiation factor 9; In vitro follicle culture; Oocyte