Objective: Nitric oxide (NO) is produced by various cells in response to mitogenic and inflammatory stimuli. This molecule plays important roles in the transmission of cellular signals, and in defense against pathogens by oxidative toxicity. In biological fluids, NO is rapidly converted to nitrite and nitrate. Therefore, the best index of total NO production is the sum of nitrite and nitrate. The most widely accepted classical method for measuring NO is the Griess method. Widely used commercial colorimetric kits involving the Griess method are very costly. In this study, we aimed to compare two different applications of Griess method for NO measurement.
Methods: We tested two identical sets of 155 human plasma samples for NO with two different applications of the Griess method. These applications involved different deproteinization and nitrate-nitrite conversion methods. The fırst application was a commercial (Cayman Chemical) NO colorimetric assay with deproteinization via ultrafiltration and nitrate-nitrite conversion using NADPH-dependent nitrate reductase, and the second one was an in-house application involving sulphanilamide and N-(1-naphthyl) ethylendiamine dihydrochloride compounds with NaOH and ZnSO4 deproteinization and VaCl3 was used for nitrate-nitrite conversion.
Results: The results with the se two different Griess applications were statistically correlated (r=0.954, p
Griess; NaOH; Nitrate reductase; Nitric oxide; Ultrafıltration; VaCl3; ZnSO4