Serum myoglobin(Mb) concentrations were measured in normal controls and hy-pothyroidism by radioimmunoassay

It was found that serum Mb levels were significantly higher in hypothyroid patients than that of controls. The time that the patients suffered the hypothyroidism is longer

the serum Mb levels is higher. A significant inverse correlation was found between serum T4 and Mb in "longterm "hypothyroidism. It means that the thyroid hormone decreasing is an important factor to the rise of serum Mb. So serum Mb can be considered one of the complementary index in treating hypothyroidism