title: Effect of nitric oxide on proliferation of human retina pigment epithelial cells.
abstract: OBJECTIVE
  To investigate the effects of exogenous and endogenous nitric oxide (NO) on the proliferation of human retina pigment epithelial (RPE) cells.
  
  
  METHODS
  We stimulated cultured human RPE cells with 3-morphosydnonimine (SIN-1) to analyse the effect of exogenous NO. Incubation with a cytokine cocktail (interleukin 1-beta + interferon gamma + tumour necrosis factor alpha) plus lipopolysaccharide (LPS) induced cells to synthesise NO endogenously. The cultures were then incubated for 48 h, after which the cells were stained with crystal violet and absorbance at 550 nm was measured spectrophotometrically.
  
  
  RESULTS
  SIN-1 inhibited human RPE cell proliferation, while haemoglobin, an NO inhibitor, almost completely blocked the inhibitory effect. On the other hand, treatment with the cytokine cocktail plus LPS did not inhibit RPE cell proliferation.
  
  
  CONCLUSIONS
  These findings confirm that exogenous NO inhibits human RPE cell proliferation, while endogenous NO has no such blocking effect.
authors.affiliation: Baskent University, School of Medicine, Department of Ophthalmology, Ankara, Turkey. gurselyilmaz@hotmail.com
authors.forename: G
authors.initials: G
authors.lastname: Yilmaz
authors.forename: P
authors.initials: P
authors.lastname: Esser
authors.forename: N
authors.initials: N
authors.lastname: Kociek
authors.forename: K
authors.initials: K
authors.lastname: Heimann
mesh_terms: D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D016207:Cytokines / Q000502:physiology; D006454:Hemoglobins / Q000502:physiology; D006801:Humans; D008070:Lipopolysaccharides; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000502:physiology*; D012160:Retina / Q000166:cytology / Q000502:physiology*; D013053:Spectrophotometry
chemical_list: D016207:Cytokines; D006454:Hemoglobins; D008070:Lipopolysaccharides; D009569:Nitric Oxide