The Effect of Methimazole-Induced Hypothyroidism on Serum Levels of Copper and Zinc in Albino Rats

Thyroid gland is one of the biggest endocrine glands. Its hormones are important in growth، development and metabolism of body. The normal activity of thyroid depends on the presence of some trace elements because they are required for the synthesis and metabolism of thyroid hormones. Trace elements such as copper (Cu) and zinc (Zn) have important role in the regulation of physiological processes. They are important for maintaining thyroid health and its normal functions. The aim of this study was to investigate serum Cu، Zn، T3، T4 levels، body mass and thyroid changes in methimazole-induced hypothy-roidism by two different doses. Twenty-one adult male rats divided into three groups. The control group received drinking water. Treated groups received two doses of meth-imazole (MMI); low dose group، 20mg/ 100ml in drinking water and high dose group، 100mg/100ml in drinking water، for 42 days. At the end of experiment، the animals were weighed. After anaesthesia and scarification، blood samples were obt-ainned. Serum levels of thyroid hormones and the trace elements، Zn and Cu، were determined by radioimmunoassay and fla-meless atomic absorption methods، respect-tively. The weight of thyroid glands was also measured. The results of the study showed that MMI-induced hypothyroidism decree-sed serum levels of T4، T3، Zn، Cu and body weight but increased thyroid weight in the treatment groups as compared with the control group (P> 0. 05). These effects were more obvious in high dose treatment group. Discussion & This study sug-gests that MMI-induced hypothyroidism decreased thyroid hormones، Zn، Cu elem-ents، body weight but increased thyroid weight. It seems that hypothyroidism exert some of the effects through the decreasing of the elements، Zn and Cu.