Effects of Hyperthyroidism on the Serum Levels of Vanadium and Manganese trace Elements in

Trace elements are important for the normal function of thyroid and prevention of its diseases. Normal activities of thyroid including the synthesis of thyroid hormones and regulation of metabolism are dependent on the presence of trace elements. On the other hand، thyroid hormones may also affect the trace element levels. In this study، we investigated the effects of induced hyperthyroidism by two different doses of levothyroxine on serum levels of manganese and vanadium. The study was performed on 24 male Wistar rats that were divided into 3 groups: Control group received drinking water. The treated groups received either a low dose (4 mg per liter) or a high dose of levothyroxine (12 mg per liter) in their drinking water for 35 days. At the end of the experiments، the animals were sacrificed under deep anesthesia and blood samples were obtained. Serum levels of hormones (T3 andT4) were measured by RIA1. The concentration of the trace elements manganese and vanadium in the serum was determined with IPC-OES2. Serum levels of T3،T4، manganese and vanadium، were significantly higher in hyperthyroidism groups that received either high or low doses of drug compared with control (P<0. 001). These increases were significantly dependent on the dose of levothyroxine. Our data suggest that hyperthyroidism induced by levothyroxine can increase serum levels of manganese and vanadium. These changes were dependent on the dose of levothyroxine.