EXPERTS IN PHYSIOLOGY: SUMMARY ON WHAT YOU NEED TO KNOW ABOUT THYROID HORMONES

Abstract

The thyroid gland secretes two important hormones, thyroxine and triiodothyronine. It is now known that a more selective regulation of the synthesis of triiodothyronine from the deiodination of thyroxine in target tissues exist. This allows a greater availability of hormone in certain tissues, according to physiological needs, and conversely protects it from excessively high levels of said hormone. The thyroid gland has the ability to store and self-regulate the entry of iodine into it and to divert hormonal synthesis towards triiodothyronine in the face of low iodine intake. In addition to nuclear receptors, other receptors for thyroid hormones are known and are located in the mitochondria and on the surface of the plasma membrane; their effects are essential in development, growth and metabolism.