Triiodothyronine (T3) is a hormone produced by the cells of the thyroid gland. Most of all, it is formed in peripheral tissues upon deiodination of the hormone thyroxine (T4). Free triiodothyronine is approximately 0.2-0.5% of the total hormone in the blood.
The norm of free triiodothyronine
The norm of free triiodothyronine depends on several factors and varies in the adult from 2.6 to 5.7 pmol / l. Norms can be considered and fluctuations in the range of 3.2 - 7.2 pmol / l.
The rate of free triiodothyronine in women is lower than in men by somewhere between 5-10%. If the norm of T3 in women increases, there are irregular and painful menstruation, and in men the mammary glands begin to increase.
What is the role of the hormone triiodothyronine?
This hormone performs the following functions:
- regulates the exchange and consumption of oxygen by various tissues of the body;
- increases heat production;
- accelerates metabolism and, in particular, protein;
- reduces the level of triglycerides and cholesterol in the blood;
- promotes tissue growth in the body;
- contributes to the normal functioning of the central nervous system;
- affects the synthesis of vitamin A in the liver;
- increases the excretion of calcium in the urine;
- activates the exchange of bone tissue;
- positively affects the work of the cardiovascular system;
- can change the metabolism of lipids.
What are the causes of increased free triiodothyronine?
The reasons for the increase in free triiodothyronine can be as follows:
- thyrotoxicosis - excessive development of the hormone by the thyroid gland;
- iodine deficiency - when goiter is formed;
- taking drugs that affect the hormonal background of the body - estrogen, oral contraceptives and other means.
How to treat elevated free triiodothyronine?
For the diagnosis of thyroid disease or with suspicion of an isolated increase in hormone secretion (the so-called T3-toxicosis), an analysis of free triiodothyronine is done. According to its results, depending on the detected disease, the doctor prescribes appropriate treatment.