title: No evidence for the presence of oogonia in the human ovary after their final clearance during the first two years of life.
abstract: BACKGROUND
  Conflicting results of studies on mouse and human have either verified or refuted the presence of oogonia/primordial germ cells in the post-natal ovary. The aim of this study was to trace whether oogonia recognized by immunohistochemical methods in the first trimester human ovary were present also in peri- and post-natal ovaries.
  
  
  METHODS
  For this study, 82 human ovaries were collected: 25 from embryos from 5 to 10 weeks post conception (wpc), 2 at 18 wpc, 32 from 32 wpc to 2 years and 23 from 2 to 32 years. Of these, 80 ovaries were fixed and paraffin-embedded and 2 (8 year-old) ovaries were processed for plastic sections. Serial sections were prepared for immunohistochemical detection of markers for oogonia: tyrosine kinase receptor for stem cell factor (SCF)(C-KIT), stage-specific embryonic antigen-4 (SSEA4), homeobox gene transcription factor (NANOG), octamer binding transcription factor 4 (OCT4) and melanoma antigen-4 (Mage-A4), while noting that C-KIT also stains diplotene oocytes.
  
  
  RESULTS
  Almost all oogonia exclusively stained for SSEA4, NANOG, OCT4 and C-KIT, whereas MAGE-A4 only stained a small fraction. At birth only a few oogonia were stained. These disappeared before 2 years, leaving only diplotene oocytes stained for C-KIT. From 18 wpc to 2 years, the medulla contained conglomerates of healthy and degenerating oogonia and small follicles, waste baskets (WBs) and oogonia enclosed in growing follicles (FWB). Medulla of older ovaries contained groups of primordial, healthy follicles.
  
  
  CONCLUSIONS
  We found no evidence for the presence of oogonia in the human ovary after their final clearing during the first 2 years. We suggest that perinatal medullary WB and FWB give rise to the groups of small, healthy follicles in the medulla.
authors.affiliation: Laboratory of Reproductive Biology, Section 5712, University Hospital of Copenhagen, Rigshospitalet, Section 5712, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. agb.lrb@rh.dk
authors.forename: A G
authors.initials: AG
authors.lastname: Byskov
authors.forename: P E
authors.initials: PE
authors.lastname: Høyer
authors.forename: C
authors.initials: C
authors.lastname: Yding Andersen
authors.forename: S G
authors.initials: SG
authors.lastname: Kristensen
authors.forename: A
authors.initials: A
authors.lastname: Jespersen
authors.forename: K
authors.initials: K
authors.lastname: Møllgård
mesh_terms: D000328:Adult; D000951:Antigens, Neoplasm / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D005260:Female; D018398:Homeodomain Proteins / Q000032:analysis; D006801:Humans; D007223:Infant; D000071317:Nanog Homeobox Protein; D009363:Neoplasm Proteins / Q000032:analysis; D050814:Octamer Transcription Factor-3 / Q000032:analysis; D009867:Oogonia; D010053:Ovary / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D055746:Stage-Specific Embryonic Antigens / Q000032:analysis
chemical_list: D000951:Antigens, Neoplasm; D018398:Homeodomain Proteins; C095204:MAGEA4 protein, human; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D009363:Neoplasm Proteins; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D055746:Stage-Specific Embryonic Antigens; C066584:stage-specific embryonic antigen-4; D019009:Proto-Oncogene Proteins c-kit