Many people know the main function of the thyroid gland, and the hormones produced by it are extremely necessary 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 precisely such a number of iodine atoms. It is formed as a result of the breakdown of another hormone of this gland - T4, when one iodine atom is split off from it. Being inactive, T4 converted to triiodothyronine becomes excessively active. So what is this hormone and what is it responsible for? Let's try to figure this out.
How important is triiodothyronine?
T3 is a hormone that controls energy metabolism in the human body, it contributes to the breakdown of energy and sends it to where it is needed. Thanks to his work, a person increases nerve conduction. This hormone is also important for bone tissue and the cardiac system, it helps activate metabolic processes in them.
What is T3 free and common?
Gland cells are capable of producing the required amount of triiodothyronine already with three iodine atoms. Having penetrated the bloodstream, this hormone binds to the molecules of protein transporters and is transported through the vessels to the tissues that need its work. However, a small amount of triiodothyronine that is not bound to protein molecules remains in the blood. This is the hormone T3 free.
The remaining free hormone T3 in combination with the one that is associated with proteins is called common. It is its amount that is considered indicative in determining the pathology of the thyroid gland.
Why is a T3 hormone test necessary?
To determine the state of the thyroid gland, the endocrinologist must give the patient a referral for blood tests for three hormones - TSH, T4, T3. The study on triiodothyronine is considered very important, since it helps to minimize diagnostic error.
For example, quite often working nodes with nodular toxic goiter reproduce the T3 hormone. Its amount can increase with diseases such as diffuse toxic goiter and Bazedova disease. If the result of the analysis shows a significant increase in the amount of triiodothyronine, then doctors are diagnosed with T3 toxicosis. This condition is quite difficult to treat with medications.
The norm of the hormone T3
Norm indicators depend on what equipment is used to conduct the study. Each laboratory makes its choice in favor of certain equipment and the necessary reagents. Therefore, it is impossible to determine such a concept as "the rate of triiodothyronine." Its quantity is considered normal if the obtained results fit into the reference boundaries (from 3.15 to 6.25 pmol / l), which are indicated on the form of the laboratory. A form is formed on the computer, and the limits of the norm and the amount of the hormone are determined on it.
T3 hormone boost
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 annoys a person, he becomes nervous, aggressive, very quickly excited. This condition is accompanied by a feeling of constant fatigue.
- The fingers begin to shake.
- The patient has an increased heart rate, tachycardia, the heart begins to work intermittently. T3 - a hormone that contributes to the occurrence of extrasystole. This condition a person feels very well and often complains to the doctor about a malfunction in the heart.
- The patient begins to lose weight rapidly.
Analysis to determine the level of triiodothyronine is a rather complicated procedure. There are frequent cases when laboratories make mistakes. You can additionally conduct a test to identify the level of two other hormones - T4 and TSH. If the results indicate that TSH is normal and T3 (hormone) is elevated, then this usually indicates an error.
Also, the analysis will be unreliable even if the value of T4 is normal, and TSH and T3 are increased. If such 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.
Lowering the hormone T3
The level of triiodothyronine can decrease if there is a disruption in the production of all the hormones that are produced by the thyroid gland. This condition occurs with the following diseases:
- Hashimoto's thyroiditis is a disease in which a person’s immunity begins to kill some thyroid cells. They are not amenable to recovery, and most often they stop working and producing hormones forever.
- Hyperthyroidism - such a disease occurs after taking certain drugs aimed at treating diffuse and nodular toxic goiter. The most dangerous means in this regard are thyreostatics such as Tyrosol, Propitsil, Merkazolil.
- Hormone levels may decline after surgery to remove the entire thyroid gland or only part of it.
- Radioactive iodine treatment also helps lower triiodothyronine levels. Such therapy is aimed at removing diffuse toxic goiter.
- Hormone levels can drop when taking products that contain large amounts of iodine. These include Amiodarone, Cordaron, and more.
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 for women expecting a baby from 6 to 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 then 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 so acutely feel the effects of hyperthyroidism. Thus, you can independently determine 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’s St. T3 hormone or total), and T4 and TSH are within the normal range, then the data obtained must be double-checked in another laboratory and the blood donated again.
Conclusion
Thus, a deviation from the norm of thyroid hormones is a serious pathology, which is accompanied by a change in health 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 thyroid gland and the whole body as a whole comes to order.