Study of oxidant/antioxidant balance and insulin resistance status in both hypo- and hyperthyroid patients: relationship between thyroid hormones and insulin resistance components

Abstract

This study aimed to determine changes in the oxidant/antioxidant status and evaluate the relationship between thyroid hormones and components of insulin resistance in dysthyroid patients. Our study was conducted on 30 women, including 10 euthyroid, 10 hypothyroidism and 10 hyperthyroid subjects. Glycemia, insulinemia and homeostasis model assessment insulin resistance index (HOMA-IR), lipids (triglycerides, total cholesterol, HDL and LDL cholesterol), thyroid hormones (TSH, FT₃ and FT₄), malondialdehyde levels and antioxidant enzymes activities (catalase, superoxide dismutase and glutathione peroxidase activities) were explored. In the hypothyroid state, IR is characterized by normal plasma glucose, hyperinsulinemia, hyperlipidemia and redox status abnormalities compared to the euthyroid group. TSH levels correlated positively with insulin and HOMA-IR, while FT₄ correlated positively with HOMA-IR and insulin in a hyperthyroid state. Thyroid dysfunctions were characterized by an imbalance of the oxidant/antioxidant system and associated with insulin resistance components.