Renin is an enzyme that is synthesized by the kidneys.
It is produced in the juxtaglomerular apparatus of the nephron, or rather in the walls of the arterioles of the renal glomeruli, from where it enters the blood and lymph. This happens when there is a change in the concentration of sodium and potassium in the blood, a decrease in blood pressure, stress, a decrease in the volume of circulating blood, i.e. renin secretion is largely controlled by the traditional endocrine feedback mechanism.
Renin acts in the body on another protein (blood glycoprotein) – angiotensinogen, specifically hydrolyzing the peptide bond between the amino acids valine and leucine. An inactive decapeptide, angiotensin I, is formed, which is then converted to the active hormone, angiotensin II, by the action of angiotensin-converting enzyme. Angiotensin II causes vasoconstriction and stimulates the secretion of aldosterone by the adrenal glands. This leads to an increase in blood pressure.
Renin study
In the course of numerous studies, scientists have identified a pattern between the stimulation of the presented component and some related factors. So it turned out to isolate a number of catalysts that induce renin to be released by the body.
Among them, in the first place is the situation when potassium in the blood is increased, or sodium is reduced. Also, the reason for triggering the mechanism is a decrease in the standard volume of circulating blood or a sharp decrease in blood pressure.
Some ordinary people who receive the results of their analyzes in their hands are interested in the question of why, during the assessment of renin, laboratory assistants prescribe indicators for aldosterone. But the relationship between these two components of the human body is proportional: the higher the rate of the main enzyme, the more aldosterone units are gaining.
The result of the development of an important element for the normal state of human health is expressed in:
- high blood pressure;
- stabilization of sodium indicators;
- normalization of water and potassium levels.
Analysis Features
In order for the result of the examination to be true, you will have to try to comply with all medical recommendations in advance. The real preparation begins with the neutralization of the negative factors of the external environment. It is they who often lay the foundation for obtaining false results, which knocks down the entire subsequent treatment program.
Blood is given on an empty stomach, after at least 8 hours of abstinence from eating. It is important on the eve of the test to exclude intense physical activity, to refuse to drink alcohol. An hour before the appointed time, you need to give up coffee, sweet juice and smoking.
Renin levels are affected by body position. It is possible to take a blood test in the supine position. In this case, it is necessary to lie down for half an hour before this. If the study is carried out in an upright position, then before taking blood, you also need to stand or lie down for half an hour.
The mechanism for studying biological material involves collecting blood in a test tube, after which the plasma is separated and sent for analysis.
Medical indications
Most often, the study of plasma renin activity and direct determination of the concentration of the component with further determination of the ratio is used to diagnose primary hyperaldosteronism.
In addition, an indication for the determination of renin can be:
- high blood pressure on an ongoing basis, which cannot be stabilized by standard methods;
- pheochromocytoma;
- mineralocorticoid therapy;
- burdened family history with the risk of developing arterial hypertension or acute cerebrovascular disorders in young people under 40 years of age;
- differential diagnosis of arterial hypertension;
- pathological conditions of the kidneys, adrenal glands;
- decrease in potassium levels.
Separately, situations are considered when the victim was diagnosed with a neoplasm in the region of the kidneys or adrenal glands. It does not matter whether it is benign or malignant.
Also, all those people who have found a narrowing of the renal artery should go to be examined. Visualization made using computed tomography or magnetic resonance equipment helps in this.
Causes of fluctuations in renin levels
Reference values depend on the laboratory, as well as in what position the analysis was taken.
Intensive sports, excessive physical activity, stress, the use of diuretics and hormonal, laxatives and caffeine, with dehydration, can lead to an increase in the indicator in the analyzes.
Renin levels normally increase during pregnancy and are associated with an increase in circulating blood volume.
Diseases in which there is an increase in the level of renin:
- arterial hypertension;
- glomerulonephritis;
- polycystic kidney disease;
- primary wrinkled kidney;
- congestive heart failure;
- pheochromocytoma;
- Addison’s disease;
- thyrotoxicosis.
When the doctor reviews the results of his ward, he will definitely take into account the information provided by other tests. We are talking about a general study of blood, urine, liver and kidney tests.
A decrease in renin levels can be observed with:
- arterial hypotension;
- syndrome or Itsenko-Cushing’s disease;
- diabetes mellitus;
- autoimmune kidney disease;
- acute renal failure;
- taking certain medications (corticosteroids and prostaglandins);
- primary hyperaldosteronism and other diseases of the adrenal glands;
- genetic disease-Gordon’s syndrome;
- intestinal damage, in which there is a loss of plasma protein with feces;
- Liddle’s syndrome, which is manifested by an increase in blood pressure and mimics hyperaldosteronism.
The simplest reason for a decrease in renin in the blood can be the abuse of salt and salty foods – an excess of sodium in the blood.
But to confirm or refute all of the above, the doctor will still have to send the ward to take a number of auxiliary tests. Only on the basis of a comprehensive examination will it be possible to draw up a correct clinical picture.