Many people know the main function of the thyroid gland, and the hormones produced by it are essential for the normal functioning of the body. The hormone T3 (triiodothyronine) is one of them, and the number "three" in its definition is explained by the content in each of its molecules of just such a number of iodine atoms. It is formed as a result of the breakdown of another hormone of this gland - T4, when one atom of iodine is split off from it. Being inactive, T4 converted to triiodothyronine becomes overly active. So what is this hormone and what is it responsible for? Let's try to figure it out.
How important is triiodothyronine?
T3 is a hormone that controls energy metabolism in the human body, it promotes the breakdown of energy and sends it to where it is needed. Thanks to his work, nerve conduction is enhanced in a person. This hormone is also important for bone tissue and the heart system, it contributes to the activation of metabolic processes in them.
What is T3 free andgeneral?
Gland cells are able to produce the required amount of triiodothyronine already with three iodine atoms. Having penetrated into the bloodstream, this hormone binds to transporter protein molecules and is transported through the vessels to the tissues that need its work. However, a small amount of triiodothyronine, not associated with protein molecules, remains in the blood. It is a free T3 hormone.
The remaining free hormone T3, combined with that which is associated with proteins, is called total. It is its quantity that is considered indicative in determining the pathologies of the thyroid gland.
Why do I need a T3 test?
To determine the state of the thyroid gland, the endocrinologist necessarily gives the patient a referral for blood tests for three hormones - TSH, T4, T3. Testing for triiodothyronine is considered very important as it minimizes diagnostic error.
For example, quite often working nodes with nodular toxic goiter reproduce the hormone T3. Its amount can also increase in diseases such as diffuse toxic goiter and Basedow's disease. If the result of the analysis shows a significant increase in the amount of triiodothyronine, then doctors make a diagnosis of T3 toxicosis. This condition is quite difficult to treat with medications.
T3 hormone norm
The norm indicators depend on what equipment is used for the study. Each laboratorymakes his choice in favor of certain equipment and the necessary reagents. Therefore, it is impossible to define such a concept as the "norm of triiodothyronine." Its amount is considered normal if the results obtained fall within the reference limits (from 3.15 to 6.25 pmol / l), which are indicated on the laboratory form. A form is formed on the computer, and the limits of the norm and the amount of the hormone are determined on it.
Increased T3 hormone
Many pathological conditions of the thyroid gland are accompanied by an increase in triiodothyronine. Often a person does not even notice such a deviation from the norm. Since T3 is a very active hormone, an increase in its amount in the blood causes the following symptoms:
- Everything irritates a person, he becomes nervous, aggressive, very quickly excited. This condition is accompanied by a feeling of constant fatigue.
- Fingers begin to shake.
- The patient has an increase in heart rate, tachycardia, the heart begins to work intermittently. T3 is a hormone that contributes to the occurrence of extrasystoles. A person feels this condition very well and often complains to the doctor about malfunctions in the heart.
- The patient begins to rapidly lose weight.
Analysis to determine the level of triiodothyronine is a rather complicated procedure. It is not uncommon for laboratories to make mistakes. You can additionally conduct a test to determine the level of two other hormones - T4 and TSH. If the results obtained indicate that TSH is normal, and T3 (hormone) is elevated, then usuallythis indicates an error.
Also, the analysis will be unreliable even if T4 is normal, and TSH and T3 are elevated. If these results are obtained, then the analysis should be retaken, because with an increase in the hormone T3, the level of TSH decreases, and T4 rises.
Decreased hormone T3
Triiodothyronine levels may decrease if all the hormones produced by the thyroid gland are disrupted. This condition occurs with the following diseases:
- Hashimoto's thyroiditis is a disease in which a person's immune system begins to kill some of the thyroid cells. They cannot be restored and most often stop working and produce hormones forever.
- Hyperthyroidism - this disease occurs after taking certain drugs aimed at treating diffuse and nodular toxic goiter. The most dangerous means in this regard are considered such thyreostatics as Tyrozol, Propicil, Mercazolil.
- Hormone levels may decrease after surgery to remove all or part of the thyroid gland.
- Treatment with radioactive iodine also reduces triiodothyronine levels. Such therapy is aimed at removing diffuse toxic goiter.
- Hormone levels may drop when taking products containing large amounts of iodine. These include "Amiodarone", "Kordaron" and others.
But not always a decrease in the level of the hormone T3 in the blood indicates the presence of a disease. This condition is typical forpregnant women between 6 and 9 months of pregnancy.
You should know that the hormones T3 and T4, as well as TSH, decrease in a certain sequence. The first is always a decrease in the level of the hormone T4, and only after that does triiodothyronine fall. This happens due to the peculiarities of the body, which is insured as a result of a decrease in the hormone T3, since it is almost 10 times more active than T4.
Thanks to this, the patient does not feel the consequences of hyperthyroidism so acutely. Thus, you can independently find out whether a laboratory error has been made. If, according to the results of the analysis, the level of triiodothyronine is lowered (and it doesn’t matter if it is St. T3 hormone or total), and T4 and TSH are within the normal range, then the data obtained should definitely be rechecked in another laboratory and donate blood again.
Conclusion
Thus, the deviation from the norm of thyroid hormones is a serious pathology, which is accompanied by a change in he alth status. In this case, drowsiness may appear, memory and speech worsen, thoughts begin to get confused, women experience a malfunction in the menstrual cycle. With timely treatment, the level of hormones can be stabilized, the work of the thyroid gland and the whole organism as a whole comes into order.
