Introduction
Thyroid hormones
The concentration of the thyroid hormone can affect the heart, connective tissue, metabolite rate, glucose metabolism, protein catabolism, cholesterol level, etc. These hormones can also affect the growth and development; specifically the development of the cortex and ganglia of the brain. Iodine obtained from the diet is utilized by thyroid gland for producing thyroid hormones including thyroxine (T4) and triiodothyronine (T3) and the rest is excreted in the urine. The thyroid hormone production is controlled by the thyrotropin (thyroid-stimulating hormone, TSH) secreted from pituitary, which is regulated by hypothalamus through generating thyrotropin-releasing hormone (TRH) (1).