Triiodothyroxine or T3 is a hormone produced by the thyroid gland on the basis of tetraiodothyroxine (T4), due to its disintegration. It is produced in a small volume, only 10%, however it is the main biologically active substance of the endocrine organ.
Often to assess the functions of the thyroid gland it is necessary to determine free T3 - what kind of hormone is it and what is it intended for, know a few. However, this form of triiodothyroxine is considered the most important component of energy metabolism in the body.
What does the thyroid hormone T3 respond to?
The precursor of the substance under consideration is tetraiodothyroxine, which contains 4 iodine molecules. T4 is a low-activity hormone, it is produced by the thyroid gland in large quantities (about 90%).
After separation of one iodine molecule from tetraiodothyroxine, T3 is formed. This hormone is 10 times more active than T4, it is responsible for the processes of energy distribution, enhancement of nervous activity, including the work of the brain. In fact, triiodothyroxine is the main stimulant of all vital processes in the body.
Once T3 enters the bloodstream, it binds to proteins. They perform a transport function, delivering the hormone to those organs and tissues, where there is an urgent need. The bound triiodothyroxine in the analyzes is called generic.
A small amount of the hormone remains in the blood unbound proteins, it is this T3 is free. Its concentration is considered to be the determining factor in the study of thyroid activity, since triiodothyroxine unbound is most active and produces the above-mentioned biological effects.
Free thyroid hormone T3
Different laboratories establish their own normal limits for the substance in question. They depend on the way of calculating its concentration, units of measure and sensitivity of the equipment used.
For highly accurate immunochemiluminescent analyzers, the values described are in the range of 2.62 to 5.69 nmol / l. In the presence of less sensitive equipment, the upper limit of the norm is usually indicated slightly higher, 5.77 nmol / l.
Because of what the hormone T3 is free increased?
Deviations from normal normal values usually indicate different pathologies or temporary conditions of the body caused by specific treatment.
The main reasons for raising the hormone T3 free:
- excess of recommended body weight;
- a newly completed hemodialysis course;
- thyroid dysfunction (temporary) after childbirth;
- myeloma in combination with a high concentration of immunoglobulin G;
- subacute or acute thyroiditis;
- chronic liver disease;
- nephrotic syndrome in the development of glomerulonephritis;
- HIV infection;
- choriocarcinoma;
- hyperestrogenia;
- porphyria ;
- diffuse toxic goiter;
- reception of synthetic thyroid hormones, various oral contraceptives, methadone, cordarone.
It is necessary urgently to address to the endocrinologist if the hormone T3 free is raised - the treatment begun in time, will help to avoid complications of the specified diseases, to prevent growth of malignant neoplasms and metastasis.
Why is the hormone T3 free?
The decrease in the amount of unbound tri-thirotoxin is not as dangerous as its increase. The main reasons for such results
- insufficiency of adrenal function;
- mental illness;
- a diet low in protein;
- hypothyroidism ;
- recovery from severe disease;
- treatment with statins, anabolic, anti-inflammatory drugs, antithyroid drugs, steroids;
- recent reception of radiocontrast solutions.