Aldosterone - what is it? Functions of aldosterone
In the kidney, two anatomical components are distinguished: a cortical and brain substance. Each of them produces certain groups of hormones.
Aldosterone - what is it?
Aldosterone is a hormone synthesized by the cortical substance of the kidney, whose function is to delay sodium ions and remove the potassium ions. The mineral corticoid is synthesized in the glomeruli of the cortical substance of the kidney. This is the only mineral corticoid that enters the bloodstream. The regulation of its production depends on renin and angiotensin, mainly angiotensin-2.Therefore, as a result of their relationship, there is a renin-angiotensin-aldosterone system( RAAS).
This system regulates the level of volume and pressure in the bloodstream, that is, water-salt balance and hemodynamics. Renin enters the bloodstream under conditions of lower blood pressure, automatically triggers mechanisms to reduce the concentration of sodium ions in the blood and simultaneously increase the level of potassium acting as antagonists. At this time, the protein angiotensin breaks down to form angiotensin-1, which under the influence of enzymes turns into angiotensin-2.This protein promotes spasmodic vascular bed, which stimulates the synthesis of aldosterone. As a result, the blood pressure level rises. What is it - aldosterone, is of interest to many.
What happens when different failures occur?
In the event of a failure in this system, pathological processes that lead to hyperproduction or, conversely, to insufficient production of mineral corticoid( hyperaldosteronism and aldosteronopenia) begin.
Activation of RAAS occurs in the following situations:
- Decreased pressure in the renal blood vessel system.
- Lack of salt elements of blood.
Stressful and extreme situations entail an increase in the tone of the sympathetic nervous system.
Functions of the hormone
There are so-called target organs of this hormone:
- The brain.
Aldosterone( what is it, we explained) affects the quantitative and qualitative composition of urine. As already mentioned above, the hormone promotes the retention of sodium ions, potassium, on the contrary, removes from the body, reducing its concentration.
Affects the vascular elements through the receptors, leads to an increase in the tone of the smooth muscle component of the vascular wall as a result of arterial pressure in the peripheral parts of the bloodstream.
Influences the brain cells. Aldosterone causes a jump in blood pressure by activating the influence of the central nervous system on a vital vascular motor center.
Sodium retention occurs not only in the kidney cells, but also in the cells of the gastrointestinal tract. In the glandular formations of the skin, on the contrary, its concentration decreases due to a change in the qualitative composition of the sweat.
The effect of this mineral corticoid is:
- Increase in the level of sodium ions in the blood plasma.
- Decreased concentration of potassium ions.
- Increased blood pressure.
in addition, the hormone aldosterone activates the synthesis of collagen fibers, which is especially noticeable in ischemia of the cardiac muscle or in cases of arterial hypertension. Thus, he takes part in the formation of the connective tissue framework of the vascular system and the entire human body.
Norm of the hormone
The aldosterone norm and its physiological value are variable, but on average its concentration in an adult is from 100 to 400 picomoles / liter, and in newborn infants from 1060 to 5,480 picomoles / liter, and at the age of the first half a year is slightly lessranges between 500-4450 picomole / liter. However, we must remember that each laboratory gives its normative values of hormones, therefore the results may differ.
Why identify the hormone aldosterone?
The purpose of determining the level of the hormone
It is as follows:
- Find out the concentration of this mineral corticoid, as well as other hormonal compounds.
- Screening study for the presence of primary hyperaldosteronism( Connes syndrome).
Alarming signals for the determination of the mineral corticoid concentration
- High blood pressure level or low salt content.
- Resistance of drugs in the treatment of hypertension or a significant jump in the level of blood pressure in young people.
- Suspicion of adrenal hypofunction.
Functions of hormones in the human body are extensive.
Preparing for the study of the level of the hormone
It is necessary to perform the following actions before the analysis:
- Restriction of the consumption of carbohydrate-containing foods( bakery products, sugar) for two weeks to a month before the study.
- The use of diuretic and antihypertensive medications, steroid preparations, as well as oral contraceptives and estrogens is prohibited for 14-30 days before the procedure.
- Exclude renin inhibitors one week before the study.
- Limit physical and emotional stress three days before the test.
- Smoking is strictly prohibited for at least 3-5 hours prior to delivery of venous blood.
And if the aldosterone in the blood is elevated?
Diseases accompanied by an elevated level of the hormone
There is a division into primary and secondary aldosteronism.
Primary is represented by diseases that are caused by the following reasons:
- Conn. Syndrome.
- Malignant and benign neoplasms that activate the synthesis of mineral corticoid.
- Hyperplastic processes of the glomerular apparatus and the adrenal gland itself.
Causes of secondary hyperaldosteronism:
- Chronic heart failure.
- Cirrhosis in combination with cirrhosis resulting from ascites.
- Nephrotic edematous syndrome.
- Syndrome of Barter.
- The dehydration of the body resulting from massive blood loss or excessive loss of intra- and extracellular fluid. Malignant renal hypertension.
Decreased hormone levels are observed with:
- Chronic adrenal insufficiency.
- Waterhouse-Frideriksen Syndrome.
- Congenital form of dysfunction of the adrenal cortex.
We described the hormone aldosterone. What it is and how to monitor its level you now know.