ACTH (the hormone) - what is it? Adrenocorticotropic hormone

Our body is based on the interaction of all its component parts – tissues and organs. However, the main regulators of their functions are biological substances of different structure. Such structures can be attributed to hormones. One of these important substances is adrenocorticotropic (ACTH) hormone.

ACTH (hormone) – what it is

This substance is produced by the pituitary gland-the main endocrine gland, responsible for performing almost all functions. For the production of ACTH are responsible eosinophilic cells of the anterior pituitary.

The Latin name of the hormone literally sounds like a “related to adrenal glands”. Transporteras with the flow of blood to them, the substance triggers these glands, which helps produce adrenal-specific substances. The mechanism of action of hormones glands data aimed at the activation of virtually all the protective mechanisms that actively manifests itself under stress.

By Itself, ACTH is a protein molecule. Its structure is quite complex: it has many sections, each of which performs a specific function (attaching to specific receptors, stabilizes the function of organs responsible for immunogene action).

The Substance is subject to circadian rhythms, ie in a certain time the concentration is more than in other moments.

Biosynthesis

How is synthesized ACTH (hormone)? What it is, is quite difficult to understand, as in the molecule are combined and the blocks of proteins (amino acids), hydroxyl groups (-OH), and characteristics of biogenic amines (-NH2). Since a large part of the molecule is a chain of amino acid residues, is conventionally considered to be a peptide or protein.

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The Substance is synthesized from so-called the precursor protein. As the basis for the synthesis of the hormone molecule acts proopiomelanocortin.

Adrenocorticotropic hormone, as already mentioned, is produced in Association with the circadian rhythm, i.e. the time of day. The synthesis also depends on the hormone – kortikoliberina (starting hormone from the hypothalamus that triggers the pituitary gland). Corticoliberin actively produced from 6 to 9 am, and its least amount was observed in the blood in the interval between 19 and 23 hours. Depending on this, and varies the amount of ACTH in the blood.

The Role of the hormone

As has been said, adrenocorticotropic hormone, is responsible for the activity of the adrenal glands. Getting them through the blood, the hormone stimulates the production of glucocorticoids-cortisol, cortisone and adrenocorticosteroids. These hormones are actively used by the body to stimulate certain cells and glands. The mechanism of action of hormones based on their binding with specific receptors located in many tissues, and vessels. As mentioned above, these hormones are “stressful”, i.e. increase the activity of the organism in the presence of danger or as a result of any pathogenic factor.

These hormones have active anti-inflammatory effect, making their synthetic derivatives have found application in medicine.

In addition, between the adrenal hormones and ACTH, there is a certain relationship: the substance increases the concentration of adrenal hormones and their excess leads to the fact that it can no longer produce ACTH (a hormone). What is this phenomenon and why it happens – is still not known, but this paradox has been called “feedback”.

Clinical significance

ACTH stimulates the activity of the adrenal glands. Without the hormone these glands are not active, which would lead to various diseases.

However, sometimes it happens so that the amount of ACTH in the blood varies, and you need definition. The hormone ACTH, the rate of which the blood should be from 9 to 46 units (PG/ml), speaks of the normal and proper functional activity of the pituitary gland. The amount of the hormone may increase or decrease (usually to the absolute absence of it in the blood).

To determine the level of this peptide ACTH is used test.

It is usually carried out if you suspect the presence of pathology. Healthy people conducting this study are not shown.

Judging by the hormone concentration in the blood, and conclude what damage is the disease process – at the level of the hypothalamic-pituitary connection either at the connection between the adrenals and pituitary gland.

Define levels of the hormone in the blood

As already mentioned, to determine the concentration of hormone needed to have ACTH-test. This procedure allows to determine whether a patient's blood the hormone.

Before the study, it is recommended not to do strenuous exercise, and to refrain from drinking alcohol and psychotropic substances. It is not recommended to take spicy and smoked food. 3 hours before the examination do not smoke.

The Blood is usually taken on an empty stomach in the morning (only if no specific instructions from the endocrinologist). In some cases (if you suspect a disease Itsenko-Kushinga), the hormone studied in the evening.

For the study used venous blood of the patient. It is determined by adrenocorticotropic hormone.

ACTH (his level) after obtaining the results compare with the reference values (normal hormone contains from 9 to 46 PG/ml). Any deviation is usually perceived as a pathology.

Causes of increasing levels of ACTH

In what diseases increased ACTH? Such pathological processes include:

• Addison's Disease (bronze disease, primary adrenal insufficiency). The level of ACTH is increased due to the fact that no hormone of the adrenal glands.
• Congenital hyperplasia.
• A Disease Itsenko-Kushinga (the amount of the hormone is increased due to a pathological concentration of corticoliberin).
• The Syndrome of ectopic ACTH production (a disease associated with the development of pituitary tissue responsible for the production of ACTH in a non-standard location).
• Nelson Syndrome.
• Paraneoplastic syndrome (tumor).
• Conditions associated with trauma or surgery.
• Virilism of the adrenal glands.
• The medication directly (directly hormones of the pituitary gland) or indirectly (affecting the hypothalamus or suppress the adrenal gland) regulate the pituitary gland.
• High stress, or extreme situation.

Decline in hormone levels

Under what conditions ACTH is lowered?

• Secondary adrenal insufficiency. The decrease in ACTH is due to the fact that adrenal hormones have developed in extremely large quantities, however, are unable to exercise their function.
• Tumor of the adrenal glands (syndrome of Itsenko-Kushinga). This education increases the number of hormone-producing tissue, which in result leads to increased levels of adrenal hormones and inhibition of synthesis of ACTH.
• The Use of ciprogeptadina. This drug is used to suppress the hunger center located in the hypothalamus. As a result, can be suppressed and the synthesis of liberidou.
• Carisoprodolhoodia tumors. Differ from tumors in the syndrome Itsenko-Kushinga, but the effect is the same.
• Using glucocorticoid drugs in large doses. Artificially reduces the natural production of adrenal hormones, however, due to the large imposed concentration ceases to produce ACTH.

Treatment of patients with altered hormone levels

How to cure the patient, if he raised adrenocorticotropic hormone?

ACTH (a hormone) can be controlled using drug therapy, the use of irradiation and surgical techniques.

Drug therapy includes the use of cytotoxic drugs (used both on increase and decrease of hormone levels). Most often they are used when confirming the presence of a tumor process. The most widely “Laditan”, “Mercaptopurine”.

Radiation therapy is used when the location of tumor in the region of the brain. Applied gamma-ray therapy or proton impact.

Surgical intervention is prescribed in case of failure of conservative treatment (drugs or irradiation). Usually you remove the adrenal gland, followed by an intensive course of chemotherapy. Brain tumors are also removed, however, the intervention is fairly complex, so it is carried out infrequently.

Complications associated with changes in hormone levels

Quite often it happens that the increased or reduced levels of ACTH can lead to various complications.

Adrenal crisis – the most common condition causing increased ACTH (a hormone). What is it?

Adrenal crisis is characterized by excessive increases in the level of hormones of the adrenal cortex, which is manifested by tachycardia, increase in pressure. Against this background, often develop heart attacks and strokes. In addition, the crisis may lead to depletion of the body, which is extremely dangerous and can lead to death.

The Decrease in the level of ACTH normally leads to the development of adrenal insufficiency, frequent bouts of fainting or collapse. In addition, the partially disturbed and sexual function (because the adrenal glands in small quantities, and produce testosterone with estrogens).

Precisely in order to prevent the development of these disorders, it is recommended to timely control the level of all hormones.