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Modulatory activity of 9‐hydroxy‐ and 9‐hydroperoxy‐octadecadienoic acid towards reactive oxygen species from guinea‐pig pulmonary macrophages

1989; Wiley; Volume: 184; Issue: 1 Linguagem: Inglês

10.1111/j.1432-1033.1989.tb15007.x

1432-1033

Ferdi Engels, Paul A. J. Henricks, Helen Van Der Vliet, Frans P. Nijkamp,

Genomics, phytochemicals, and oxidative stress

As guinea‐pig pulmonary macrophages (PM) synthesize the linoleic acid metabolite 9‐hydroxy‐octadecadienoic acid (9‐OH‐Lin) under non‐stimulated conditions in relatively large quantities, we investigated whether this product has an effect on the macrophage's own phagocytic cell function. 9‐OH‐Lin, and also its hydroperoxy precursor 9‐hydroperoxy‐octadecadienoic acid (9‐OOH‐Lin), influenced the generation of PM chemiluminescence, a measure of the production of reactive oxygen species. The generation of lucigenin‐enhanced chemiluminescence by stimulated and non‐stimulated PM was inhibited concentration‐dependently. Inhibition was observed at concentrations as low as 10 nM. Since 9‐OH‐Lin and 9‐OOH‐Lin also inhibited the generation of chemiluminescence by a cell‐free enzyme system, i.e. xanthine/xanthine oxidase, the inhibitory effects might represent a scavenging activity towards reactive oxygen species. 9‐OH‐Lin and 9‐OOH‐Lin did not influence other phagocytic cell functions, e.g. PM phagocytic capacity, the aggregatory response to the calcium ionophore A23187, or the release of lysosomal enzymes. The effects of 9‐OH‐Lin and 9‐OOH‐Lin could be ascribed to the hydroxy and hydroxyperoxy moiety, respectively, as evidenced by lack of effect of the native fatty acid linoleic acid. We conclude that the formation of 9‐OH‐Lin and 9‐OOH‐Lin by PM may represent a regulatory mechanism towards the cell's own activity by modulating reactive oxygen species.