The effect of hypothyroidism, hyperthyroidism, and their treatment on parameters of oxidative stress and antioxidant status

Hüsamettin Erdamar 1 , 1 , Hüseyin Demirci 2 , 2 , Halil Yaman 3 , 3 , M. Kemal Erbil 4 , 4 , Tolga Yakar 5 , 5 , Banu Sancak 6 , 6 , Sehri Elbeg 7 , 7 , Gürsel Biberoğlu 8 , 8  and İlhan Yetkin 9 , 9
  • 1 Department of Medical Biochemistry, Tunceli Government Hospital, Tunceli, Turkey
  • 2 Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Ankara, Turkey
  • 3 Department of Biochemistry, Gulhane School of Medicine, Ankara, Turkey
  • 4 Department of Biochemistry, Gulhane School of Medicine, Ankara, Turkey
  • 5 Department of Gastroenterology, Beytepe Military Hospital, Incek, Ankara, Turkey
  • 6 Department of Medical Biochemistry, Gazi University Faculty of Medicine, Ankara, Turkey
  • 7 Department of Medical Biochemistry, Gazi University Faculty of Medicine, Ankara, Turkey
  • 8 Department of Pediatrics, Gazi University Faculty of Medicine, Ankara, Turkey
  • 9 Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Ankara, Turkey

Abstract

Background: Free radical-mediated oxidative stress has been implicated in the etiopathogenesis of several autoimmune disorders. Also, there is growing evidence supporting the role of reactive oxygen species in the pathogenesis of thyroid disorders. The aim of this study was to investigate the influence of hypothyroidism, hyperthyroidism, and their treatments on the metabolic state of oxidative stress, and antioxidant status markers.

Methods: A total of 20 newly diagnosed patients with overt hypothyroidism due to Hashimoto's thyroiditis, 20 patients with overt hyperthyroidism due to Graves' disease, and 20 healthy subjects as the control group were enrolled in the study. Fasting blood samples (12 h), taken at the initiation, after the 30th and 60th day of therapy were analyzed for malondialdehyde, nitrite, vitamin E, vitamin A, β-carotene, ascorbate, and myeloperoxidase and superoxide dismutase activity. No patient presented additional risk factors for increased reactive oxygen species levels.

Results: Malondialdehyde, nitrite, vitamin E, and myeloperoxidase activity increased in patients with hypothyroidism. After 2 months, the levels of nitrite and vitamin E were reduced to control levels by treatment. The patients with hyperthyroidism had increased levels of malondialdehyde and myeloperoxidase activity in comparison with the controls. Treatment with propylthiouracil attenuated these increments after 1 month.

Conclusions: Our results reveal an increased generation of reactive oxygen species and impairment of the antioxidant system in patients with hyperthyroidism, and particularly in patients with hypothyroidism. These findings indicate that thyroid hormones have a strong impact on oxidative stress and the antioxidant system.

Clin Chem Lab Med 2008;46:1004–10.

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Clinical Chemistry and Laboratory Medicine ( CCLM) publishes articles on novel teaching and training methods applicable to laboratory medicine. CCLM welcomes contributions on the progress in fundamental and applied research and cutting-edge clinical laboratory medicine. It is one of the leading journals in the field, with an impact factor of over three. CCLM is the official journal of nine national clinical societies and associated with EFLM.

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