RESUMO
Erythrocyte, plasma, and serum antioxidant activities were studied in patients with newly diagnosed and untreated toxic multinodular hyperthyroid goiter and compared to healthy control subjects. Erythrocyte antioxidant enzyme activities, glutathione, malondialdehyde, and ceruloplasmin levels were significantly increased, whereas serum vitamin E, plasma vitamin C, and selenium levels were decreased in hyperthyroid patients compared to control subjects. The findings show that untreated toxic multinodular goiter causes profound alterations in components of the antioxidant system in erythrocytes indicative of increased oxidative stress. Taken together, these data suggest that hyperthyroid patients may benefit from dietary supplements of antioxidants.