Nitrite production by stimulated human polymorphonuclear leukocytes supplemented with azide and catalase
The formation of nitric oxide by human phagocytes as measured by nitrite production is controversial. We report here that nitrite production by phorbol myristate acetate (PMA)-stimulated human polymorphonuclear leukocytes (PMN) is considerably increased by the addition of azide and a further increase occurs when catalase also is added. Nitrite production by the PMN-PMA-azide-catalase system is unaffected by superoxide dismutase or monomethylarginine but is markedly reduced by the substitution of chronic granulomatous disease for normal neutrophils. The stimulated neutrophils could be replaced by the H2O2-generating enzyme system glucose-glucose oxidase. These findings suggest that nitrite production does not, in this instance, reflect nitric oxide synthase activity by human neutrophils but rather the catalase-catalyzed conversion of azide to nitrite in the presence of H2O2 generated by the stimulated PMN.