Nitric oxide reacts with intracellular glutathione and activates the hexose monophosphate shunt in human neutrophils: evidence for S-nitrosoglutathione as a bioactive intermediary.

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RESUMO

We performed experiments to determine whether nitric oxide promoted the formation of intracellular S-nitrosothiol adducts in human neutrophils. At concentrations sufficient to inhibit chemoattractant-induced superoxide anion production, nitric oxide caused a depletion of measurable intracellular glutathione as determined by both the monobromobimane HPLC method and the glutathione reductase recycling assay. The depletion of glutathione could be shown to be due to the formation of intracellular S-nitrosoglutathione as indicated by the ability of sodium borohydride treatment of cytosol to result in the complete recovery of measurable glutathione. The formation of intracellular S-nitrosylated compounds was confirmed by the capacity of cytosol derived from nitric oxide-treated cells to ADP-ribosylate glyceraldehyde-3-phosphate dehydrogenase. Depletion of intracellular glutathione was accompanied by a rapid and concomitant activation of the hexose monophosphate shunt (HMPS) following exposure to nitric oxide. Kinetic studies demonstrated that nitric oxide-dependent activation of the HMPS was reversible and paralleled nitric oxide-induced glutathione depletion. Synthetic preparations of S-nitrosoglutathione shared with nitric oxide the capacity to inhibit superoxide anion production and activate the HMPS. These data suggest that nitric oxide may regulate cellular functions via the formation of intracellular S-nitrosothiol adducts and the activation of the HMPS.

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