Thyroid Disorders and their Relevance to Response to Oxidative Challenge

Abstract

AbstractObjective: The extent to which thyroid hormones T4, T3 and thyroid stimulating hormone (TSH) changes can influence lipid peroxidation in plasma as indicated by malondialdehyde MDA levels in response to in vitro challenge with H2O2 (5, 10 or 15 mM), as well as, the antioxidant status reduced glutathione (GSH) as the major endogenous antioxidant to be investigated in patient with various thyroid disorders.Methods: The study included: group (1) twenty hyperthyroid patients and group (2) seventeen hypothyroid patients. Each of these groups was studied by comparing their data with those of twenty-five, sex and age matched healthy control subjects. Hormonal assay was performed using RIA technique. Blood samples were heparinized to obtain plasma to evaluate the susceptibility of plasma to oxidation of lipids to produce malondialdehyde in response to in vitro challenge with 5, 10 or 15 mM H2O2. Reduced glutathione content of erythrocytes was measured as indicator for antioxidant state.Results: Plasma of both hyperthyroid and hypothyroid patients showed greater levels of MDA (130% and 14%, respectively) over the control. Only hyperthyroid patient’s plasma expressed a greater susceptibility to in vitro H2O2 challenge, as compared to both hypothyroid and control groups. Reduced glutathione contents were lowered in both hyper- and hypothyroid erythrocytes by 40% and 45%, respectively, as compared to controls.Conclusion: These results indicate that thyroid disorders could precipitate several biochemical changes in tissue that predispose them to oxidative injury. Thus we suggest the use of antioxidants as supplement with the regular therapy of thyroid disorders, in a hope to minimize or delay the chronic complications of thyroid diseases.Key words: hyperthyroidism, hypothyroidism, MDA, GSH.