title: Cell plating density alters the ratio of estrogenic to progestagenic enzyme gene expression in cultured granulosa cells.
abstract: OBJECTIVE
  To determine if initial cell plating density alters steroidogenesis and the E(2):P ratio in granulosa cells in long-term serum-free culture.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Academic institution.
  
  
  METHODS
  Cattle of slaughterhouse origin.
  
  
  METHODS
  Culture of granulosa cells in vitro at different cell plating density.
  
  
  METHODS
  Steroid secretion was measured by RIA, mRNA levels were measured by real-time polymerase chain reaction, and cell death was assessed by flow cytometry.
  
  
  RESULTS
  Low plating density favored E(2) secretion and mRNA encoding estrogenic enzymes, whereas higher density inhibited E(2) secretion and enhanced P secretion and levels of mRNA encoding progestagenic enzymes. Increasing plating density decreased the E(2):P ratio and cell health.
  
  
  CONCLUSIONS
  Lower cell density favors an estrogenic granulosa cell phenotype, whereas higher density favors luteinization. Serum-free culture systems should be optimized with this in mind.
authors.affiliation: Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, St. Hyacinthe, Québec, Canada.
authors.forename: Valério M
authors.initials: VM
authors.lastname: Portela
authors.forename: Gustavo
authors.initials: G
authors.lastname: Zamberlam
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Price