H2O2 generation is a limiting step in thyroid hormone bio-synthesis. Biochemical studies have confirmed that H2O2is generated by a thyroid Ca 2+ /NADPH-dependent oxidase. Decreased H2O2 availability may be another mechanism of inhibition of thyroperoxidase activity produced by thio-ureylene compounds, as propylthiouracil (PTU) and methimazole (MMI) are antioxidant agents. Therefore, we analyzed whether PTU or MMI could scavenge H2O2or inhibit thyroidNADPHoxidase activityin vitro.
