Xanthine oxidoreductase catalyses the reduction of nitrates and nitrite to nitric oxide under hypoxic conditions. O'Byrne, S., Shirodaria, C, Millar, T, Stevens, C, Blake, D, and Benjamin, N. 2000. Inhibition of platelet aggregation with glyceryl trinitrate and xanthine oxidoreductase. Winrow, V., Millar, TM, and Blake, DR. 1997. Redox modulation of haem oxygenase-1 transcription in endothelial cells.
Hypoxia upregulates xanthine oxidase in synovial endothelial cells.