 A phagocyte-type oxidase, similar to that responsible for the production of large amounts of reactive oxygen species (ROS) in neutrophil granulocytes, with resultant antimicrobial activity, has been postulated to function in the kidney as an oxygen sensor that regulates the synthesis of erythropoietin in the renal cortex.Nox4 protects the vasculature against inflammatory stress.Nox-dependent reactive oxygen species modulation by amino endoperoxides can induce apoptosis in high Nox4-expressing cancer cells.