title: Estradiol and progesterone regulate the proliferation of human breast epithelial cells.
abstract: OBJECTIVE
  To study the effects of estradiol and progesterone on the proliferation of normal human breast epithelial cells in vivo.
  
  
  METHODS
  Double-blind randomized study.
  
  
  METHODS
  Departments of gynecology and of cell biology at a university hospital.
  
  
  METHODS
  Forty postmenopausal women with untreated menopause and documented plasma FSH levels of >30 mIU/mL and estradiol levels of <20 pg/mL.
  
  
  METHODS
  Daily topical application to both breasts of a gel containing a placebo, estradiol, progesterone, or a combination of estradiol and progesterone during the 14 days preceding esthetic breast surgery or excision of a benign lesion.
  
  
  METHODS
  Plasma and breast tissue concentrations of estradiol and progesterone. Epithelial cell cycles were evaluated in normal breast tissue by counting mitoses and performing quantitative proliferating cell nuclear antigen immunolabeling analyses.
  
  
  RESULTS
  Increasing the estradiol concentration enhanced the number of cycling epithelial cells, whereas increasing the progesterone concentration significantly limited the number of cycling epithelial cells.
  
  
  CONCLUSIONS
  Exposure to progesterone for 14 days reduced the estradiol-induced proliferation of normal breast epithelial cells in vivo.
authors.affiliation: University of Liège, Belgium.
authors.forename: J M
authors.initials: JM
authors.lastname: Foidart
authors.forename: C
authors.initials: C
authors.lastname: Colin
authors.forename: X
authors.initials: X
authors.lastname: Denoo
authors.forename: J
authors.initials: J
authors.lastname: Desreux
authors.forename: A
authors.initials: A
authors.lastname: Béliard
authors.forename: S
authors.initials: S
authors.lastname: Fournier
authors.forename: B
authors.initials: B
authors.lastname: de Lignières
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000166:cytology / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D004311:Double-Blind Method; D004847:Epithelial Cells / Q000187:drug effects; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011374:Progesterone / Q000097:blood / Q000494:pharmacology*
chemical_list: D011374:Progesterone; D004958:Estradiol