The thyroid gland is the largest organ of the endocrine system. It is located on the neck on both sides of the upper part of the trachea and looks like a butterfly. The thyroid gland follicles normally synthesize the hormones triiodothyronine (T 3 ) and tetraiodothyronine (T 4 or thyroxine). Since the thyroid gland in Latin sounds like “glandula thyroidaa,” the hormones that it synthesizes are called thyroid glands. They bind to the protein with the formation of thyroglobulin, and in this form can persist in the follicles of the gland for several months. When necessary, thyroglobulin breaks down, hormones are released. Then they enter the circulatory system and are distributed throughout the body by special carrier proteins, and then penetrate the tissues of our body.
Water, Mill, and Thyroid Hormones
It is said that the thyroid gland "pours water into the mill of our life." This means that normally the thyroid hormones provide a person with activity, good mood, and children - growth and development. If the thyroid gland does not work well - “it pours little water”, then “the mill spins slowly”, that is, a person becomes inhibited, lethargic, and children do not grow, their mental development is delayed. How can this be explained scientifically?
The primary biochemical effect of thyroid hormones is the activation of protein synthesis . Thyroid hormones normally penetrate into the cells, interact with the DNA of the cell, changing the activity of certain parts of the genome. As a result, the synthesis of mainly enzyme proteins and receptor proteins is enhanced. Both those and others regulate a metabolism as a whole.
Thyroid Performance
Typically, blood is given to test the level of thyroid hormones for suspected diseases of this gland.
Normal values of hormones and other indicators of the thyroid gland are shown in table 1.
| Table 1. The norm of thyroid hormones in women |
| TTG | μme / ml | 0.4-4.0 |
| T 3 total | nmol / l | 1.2-2.7 |
| T 3 St. | pmol / l | 2,3-6,4 |
| T 4 total | nmol / l | 55-156 |
| T 4 St. | pmol / l | 10.3-24.6 |
| Thyroglobulin | ng / ml | ≤56 |
| Thyroxin binding globulin | nmol / l | 259-575.6 |
| Antibodies to Tereoglobulin | μme / ml | ≤65 |
| Thyroid Peroxidase Antibodies | ≤35 |
| TSH receptor antibodies | A piece of chalk | ≤1.8 negative |
| ≥2.0 positive |
Thyroglobulin, antibodies to thyroglobulin
The production of thyroid hormones occurs in thyroid cells - thyroid cells. For the synthesis of hormones, the amino acid tyrosine and the trace element iodine are needed. Tyrosine is part of the thyroglobulin molecule. Two iodine atoms and a phenolic group join tyrosine. The resulting compound is called tyrone. Another iodine can join it to form triiodothyronine, or the T 3 hormone, and another iodine with it to form tetraiodothyronine (tetra means 4), or the hormone T 4 , also called thyroxine.
The resulting hormones are stored in the cells of the gland as part of thyroglobulin. As necessary, the complex of hormones and thyroglobulin is destroyed, hormones enter the bloodstream to perform its function. Together with them, a small amount of iodine and thyroglobulin enters the bloodstream. This is important to know in order to understand the mechanism of development of autoimmune diseases. Previously, it was believed that thyroglobulin enters the blood only with pathology of the thyroid gland, and therefore causes the formation of antibodies to itself. It has now been established that thyroglobulin is normal in the blood.
Thyroid Peroxidase Antibodies
As already mentioned, thyroid hormones are synthesized from tyrosine and iodine. The source of iodine is food, especially seafood. Iodine coming from food is inorganic, absorbed in the intestine, into the bloodstream, from where it is captured by the thyroid gland. In order for such iodine to become active and able to integrate into organic molecules, it must be oxidized. It is oxidized by hydrogen peroxide with the participation of the enzyme iodide peroxidase, which is also called thyroid peroxidase. Without this enzyme, hormones will not be synthesized, even if iodine enters the body in the right amount.
Free and bound T4, thyroxin-binding globulin
Normally, in women, the thyroid hormones T 4 in the blood are 99.95% bound. Hormones bind to special carrier proteins. This protects the hormone from destruction and creates its reserve. In 80% of cases, such a protein is a thyroxin-binding globulin. In the free form in the blood plasma there is an insignificant amount of thyroxine, but it is this one - free thyroxine and has activity.
Free and bound T3
In the blood, 99.5% of the hormone T 3 is in bound form, 90% of it joins the thyroxin-binding hormone. Of the total amount of T 3 in the blood, only 15% is synthesized in the follicles of the thyroid gland, the rest of the hormone obtained in the liver by cleavage of one iodine from T 4 . As can be seen from table No. 1, in blood T 3 is less than T 4 , but its physiological activity is 4 times higher. In addition, studies have shown that in cells they perform a hormonal function (they react with nuclear receptors, thus affecting the DNA of the cell) namely T 3 . This confirms the view that the true thyroid hormone is normally T 3 , and T 4 is a prohormone.
TTG
Thyroid hormones perform an extremely important function in the body - they regulate protein synthesis in all cells of the body, so their production is controlled at several levels:
- cerebral cortex;
- the hypothalamus along the efferent nerves;
- hypothalamus through the pituitary gland;
- depending on the iodine content in the body.
Yet the main way to regulate the synthesis of hormones is the third of these. In the hypothalamus, a signal is formed that acts on the pituitary gland and stimulates the production of thyroid-stimulating (that is, directed to the thyroid gland) hormone - TSH. It activates the synthesis of thyroglobulin in the thyroid gland, which is a precursor of thyroid hormones. When a sufficient amount of these hormones is produced, the formation of TSH is suppressed, the thyroid hormones normally stop synthesizing (feedback). With the help of such complex mechanisms, the thyroid gland is finely regulated to adapt to the changing needs of the whole organism.
Changing the content of TSH in the blood is the first bell of thyroid dysfunction. If the TSH level in women is normal, then the thyroid hormones will probably also be in order.
Pregnancy and Thyroid
The main regulator of thyroid hormone production is TSH. During pregnancy, the placenta produces chorionic gonadotropin, which also activates the production of thyroid hormones. Therefore, in pregnant women, the norm of the content of thyroid hormones in the blood rises. Chorionic gonadotropin begins to be synthesized 6 hours after fertilization, its presence in the blood inhibits the synthesis of TSH. By around the 4th month the situation is normalizing. Therefore, the level of TSH in serum changes during pregnancy.
The synthesis of thyroid hormones is also affected by estrogens. During pregnancy, they become larger, and the thyroid gland secretes hormones more actively. Then the mechanism of deactivation of hormones in the blood by the thyroxin-binding globulin is turned on, its synthesis in the liver increases, which will be reflected in the results
Another factor in the activation of the gland in the second half of pregnancy is a decrease in the iodine content in the blood due to its distraction to the fetoplacental complex. Iodine, in addition, is strongly excreted in urine in pregnant women.
All of these factors lead to gland hyperfunction. An elevated level of total T 3 and total T 4 will be recorded in the blood, free T 3 and T 4 will be normal.
| Table 2. The norm of thyroid hormones in pregnant women |
| TTG | μme / ml | 0.2-3.5 |
| T 4 total | nmol / l | I trimester 100-209 |
II, III trimester 117-236 |
| T 4 St. | pmol / l | I trimester 10.3-24.6 |
II, III trimester 8.2-24.7 |
Interpretation of the results of the analysis of the thyroid gland
To assess the functioning of the thyroid gland, laboratory (determination of the hormone content in the blood) and instrumental (ultrasound) studies are used.
The condition of the body in which there are no signs of deviations in the thyroid gland is called euthyroidism. A condition in which signs of excessive work of the gland (hyperfunction) are detected are called hyperthyroidism; insufficient functioning of the gland (hypofunction) - hypothyroidism.
The norm in the analysis of thyroid hormones in women is much less common than in men, since it is women who are susceptible to various thyroid pathologies.
A variety of environmental factors lead to damage to thyroid cells, impaired function, and the development of hypo- or hyperthyroidism. Peptide bioregulators can help repair damaged cells. In Russia, the first brand of peptide bioregulators are cytamines - a line of 16 drugs aimed at different organs. To improve thyroid function, a peptide bioregulator has been developed - . The components for tyramine are obtained from the thyroid glands of cattle, they are a complex of proteins and nucleoproteins that have a selective effect on thyroid cells, which helps to restore its function. Tyramine is recommended for use in violation of the thyroid gland, hypo- and hyperfunction, tumor processes in the glandular tissue. As a prophylactic, tyramine is advisable to use for people living in areas endemic for thyroid diseases. Tiramine is also recommended for older and older people to maintain thyroid function.
| Table 3. Typical changes in blood parameters in thyroid pathologies |
| T 3 St. | T 4 St. | TTG | AT-TG | at-tpo |
| Primary hypothyroidism. | Low or normal | Low or normal | Tall |
| Secondary hypothyroidism. | Low | Low | Low |
| Primary hyperthyroidism. | Tall | Tall | Low |
| Autoimmune thyroiditis. The thyroid gland is inflamed. | Possible increase and decrease in hormones | Tall | Tall |
Table No. 4 presents diseases and various conditions of the body, which are characterized by changes in the performance of the thyroid gland.
| Table 4. Diagnosis of various conditions according to the results of a blood test |
| Increase | Lowering |
T 4 total | Thyrotoxic goiter; pregnancy, postpartum thyroid dysfunction; hormone-producing tumors of the thyroid gland, inflammation of the gland; pathology of the liver and kidneys, obesity; taking medications - thyroid hormones, iodine-containing, estrogens, insulin, oral contraceptives; HIV infection, AIDS. | Hypothyroidism; taking medications - antithyroid drugs, iodides, glucocorticoids, non-steroidal anti-inflammatory drugs, antitumor, anti-tuberculosis, hypolipidemic, anticonvulsant, antifungal agents, lithium salts, furosemide; significant iodine deficiency in the body. |
T 4 sv | Toxic goiter; thyroiditis; postpartum gland dysfunction, nephrotic syndrome, obesity; taking medications - oral contraceptives, estrogens, thyroid drugs, TSH; prolonged application of a tourniquet for taking blood. | Primary hypothyroidism, which manifests itself as: autoimmune thyroiditis, endemic goiter, neoplasms of the thyroid gland, removal of part or all of the gland; secondary hypothyroidism; tertiary hypothyroidism resulting from a brain injury or inflammation in the hypothalamus; deficiency in protein and iodine intake; taking drugs - anabolic steroids, anticonvulsants , lithium preparations , oral contraceptives, an overdose of thyreostatics; contact with lead, surgery, dramatic weight loss in obese women. |
| T 3 total and St. | Thyrotoxic goiter; inflammation of the gland, some tumors of the gland, isolated T 3 toxicosis, impaired synthesis postpartum dysfunction of the gland, pathology of the kidneys and liver, hemodialysis, weight gain; taking drugs - estrogen, levothyroxine, oral contraceptives. | Hypothyroidism; severe illness, mental illness; insufficient protein intake; taking drugs - antithyroid drugs, glucocorticoids, beta-blockers, non-steroidal anti-inflammatory, lipid-lowering drugs, oral contraceptives, radiopaque agents. |
| TTG | Hypothyroidism; pregnancy; pituitary tumors; thyroid hormone immunity, adolescent hypothyroidism, decompensated adrenal insufficiency, severe general and mental illnesses, gallbladder removal, significant physical exertion, hemodialysis, lead poisoning; taking drugs - anticonvulsants, antipsychotics, beta-blockers, iodides, morphine, prednisolone, radiopaque agents. | Toxic goiter, thyrotoxicosis; insufficient blood supply to the pituitary gland; injuries, starvation, stress, depression, severe mental illness; taking drugs - T 3 and T 4 , somatostatin, corticosteroids, anabolic steroids, cytostatics, beta-adrenergic agonists, treatment of hyperprolactinemia. |
Using this data, you can decipher your own analysis results, but it is better to contact a specialist.