title: Adaptation of the nitrate reductase and Griess reaction methods for the measurement of serum nitrate plus nitrite levels.
abstract: Nitrite and nitrate determinations in biological fluids are increasingly being used as markers of nitric oxide production. We have modified a nitrate reductase and Griess reaction method for the measurement of serum nitrate and nitrite in ultrafiltrated samples using a microtitre plate. The recoveries of nitrate and nitrite were 95% (range = 86-113%) and 100% (range = 92-109%), respectively. The intra and inter assay coefficients of variation for nitrate plus nitrite in the concentration range 40-50 microM were 9.1% and 7.8%, and in the concentration range of 2.5-10 microM 23.4% and 25.5%, respectively. At its lower limit the assay is able to detect 125 pmoles of nitrate plus nitrite in 50 microL of sample (2.5 mumol/L). A mean serum nitrate plus nitrite level of 32.8 mumol/L (SD 12.3) was measured in 24 healthy adult volunteers (12 men and 12 women), no age or sex differences were noted.
authors.affiliation: Department of Neuroimmunology, Institute of Neurology, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Giovannoni
authors.forename: J M
authors.initials: JM
authors.lastname: Land
authors.forename: G
authors.initials: G
authors.lastname: Keir
authors.forename: E J
authors.initials: EJ
authors.lastname: Thompson
authors.forename: S J
authors.initials: SJ
authors.lastname: Heales
mesh_terms: D000328:Adult; D001798:Blood Proteins / Q000737:chemistry; D005260:Female; D006801:Humans; D008297:Male; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000737:chemistry*; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001798:Blood Proteins; D009566:Nitrates; D009573:Nitrites; D009565:Nitrate Reductases; D050901:Nitrate Reductase