NOX4 and hyperinsulinemic hypoglycemia, familial, 4: However, it could be observed that the production of H2O2 is so increased in the thyroid follicles due to the actions of enzymes such as NOX4, that the NADPH depletion induced by G6PD deficiency could not be sufficient to significantly inhibit the flow of H2O2, but enough to hinder glutathione-dependent antioxidant activity.