Association between thyroid hormones, lipids and oxidative stress biomarkers in overt hypothyroidism.
BACKGROUND
The aim of this study was to investigate the effect of hypothyroidism on lipid peroxidation and the antioxidant profile, as well as to evaluate the interaction between thyroid hormones and biomarkers of oxidative stress in patients with overt hypothyroidism. We also evaluated the influence of cholesterol concentrations on biomarkers of oxidative stress in these same patients.


METHODS
Total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and vitamin E were measured in 20 subjects with overt hypothyroidism (OH) and 20 controls.


RESULTS
TC, LDL cholesterol, triglycerides, TBARS, SOD, CAT, and vitamin E were significantly higher in the OH group. Significant correlation was observed for TSH and SOD, CAT, vitamin E and TBARS. Correlation was observed for triiodothyronine (T3) and SOD, CAT, vitamin E and TBARS. Significant correlation was also observed for free thyroxine and vitamin E and TBARS. However, correlation between T3 and CAT remained significant after controlling for TC concentrations.


CONCLUSIONS
Overt hypothyroidism is associated with an increase in oxidative stress, and hypercholesterolemia has a stronger influence on development of oxidative stress in hypothyroid conditions compared with thyroid hormones.
Santi
Adriana
A
Departamento de Fisiologia e Farmacologia, Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, RS, Brazil.
Duarte
Marta Maria Medeiros Frescura
MM
Moresco
Rafael Noal
RN
Menezes
Charlene
C
Bagatini
Margarete Dulce
MD
Schetinger
Maria Rosa Chitolina
MR
Loro
Vania Lucia
VL
D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D002784:Cholesterol / Q000378:metabolism; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000378:metabolism*; D015227:Lipid Peroxidation; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D013963:Thyroid Hormones / Q000378:metabolism*
D000975:Antioxidants; D015415:Biomarkers; D013963:Thyroid Hormones; D002784:Cholesterol