The Thyroid Gland And Its Hormones

To understand the hypothyroidism, some knowledge about the thyroid gland and its hormones is essential.

The thyroid gland produces hormones that accelerate and in other wise regulate metabolism. A part of metabolism is the process of breaking down energy containing nutrients, and using the energy to produce molecules that all the processes and activities in the body use as fuel. Another part is the production of molecules that the body use as building materials.

The thyroid makes four hormones: Thyroxin (T4), triiodothyronine (T3), diiodothyronine (T2) and monoiodothyronine (T1).  The hormones contain iodine, and the figures tell about the number of iodine atoms in each hormone molecule. T3 is not made directly, but is produced from T4. T3 is a more efficient hormone than T4. Therefore this conversion is important.

The pituitary, a gland under the brain, produces a hormone called thyrotropin or thyroid stimulating hormone (TSH) that enhances the activity of the thyroid gland. If the body has too less thyroid hormone in the blood, the pituitary produces more thyrotropin. This makes the thyroid gland speed up its own production. By a too heavy thyroid hormone concentration, less thyrotropin is produced by the pituitary, and the thyroid gland slows down. This feed-back mechanism regulates the metabolism of the whole body.