title: Endothelin-1 and Nitric Oxide Levels in Exudative Age-Related Macular Degeneration.
abstract: OBJECTIVE
  To evaluate plasma levels of endothelin-1 (ET-1) and nitric oxide (NO) in patients with exudative age-related macular degeneration (AMD).
  
  
  METHODS
  In this study, ET-1 levels, as well as nitrite plus nitrate concentrations as an indicator of plasma NO level, were measured in the plasma of 20 subjects with exudative AMD and compared with 20 healthy age and sex matched controls.
  
  
  RESULTS
  Mean plasma ET-1 level was significantly higher in exudative AMD patients as compared to control subjects (0.35 ± 0.06 fmol/ml versus 0.17 ± 0.03 fmol/ml, P = 0.015). Patients with exudative AMD also showed significantly lower mean plasma levels of nitrite plus nitrate as compared to the controls (58.9 ± 2.7 µmol/l versus 82.6 ± 5.9 µmol/l, P = 0.001).
  
  
  CONCLUSIONS
  Increased concentrations of ET-1 and reduced levels of NO in the plasma may suggest an imbalance between vasoconstrictor and vasodilator agents, respectively, as a reflection of endothelial dysfunction in the pathogenesis of AMD. These findings may also imply the role of vasoconstriction in exudative AMD.
authors.affiliation: Department of Ophthalmology, Turgut Özal University Medical School, Ankara, Turkey.
authors.forename: Yϋksel
authors.initials: Y
authors.lastname: Totan
authors.affiliation: Department of Biochemistry, Yıldırım Beyazıt University Medical School, Ankara, Turkey.
authors.forename: Cemile
authors.initials: C
authors.lastname: Koca
authors.affiliation: Department of Ophthalmology, Hacettepe University Medical School, Ankara, Turkey.
authors.forename: Mesut
authors.initials: M
authors.lastname: Erdurmuş
authors.affiliation: Department of Ophthalmology, Mustafa Kemal University Medical School, Hatay, Turkey.
authors.forename: Uğurcan
authors.initials: U
authors.lastname: Keskin
authors.affiliation: Department of Biochemistry, Yıldırım Beyazıt University Medical School, Ankara, Turkey.
authors.forename: Ramazan
authors.initials: R
authors.lastname: Yiğitoğlu
keywords: Age-related Macular Degeneration; Endothelial Dysfunction; Endothelin-1; Nitric Oxide