Angiotensin II | Laboratory research

General Information

Angiotensin II is an active, potent, but labile (unstable) peptide. It is produced from angiotensin I with the participation of angiotensin-converting enzyme. Its production is controlled by renin, blood pressure and blood volume, sodium balance, and aldosterone levels.

Angiotensin II participates in the renin-angiotensin cascade, blood pressure regulation, fluid, electrolyte and homeostasis maintenance.

The renin-angiotensin system contains one active peptide - angiotensin II and two specific receptors (AT1 and AT2), the activation of which gives contradictory effects.

As a result of the decrease in blood pressure, the blood supply of the juxtaglomerular apparatus (in the kidney) decreases, which is followed by the release of renin into the circulation.

Renin acts on angiotensinogen and converts it to angiotensin I (ANG-1). Through angiotensin-converting enzyme, angiotensin I is converted to angiotensin II (this enzyme is particularly active in the pulmonary capillaries). The renin-angiotensin system directly affects the smooth muscles of blood vessels and ensures the maintenance of blood vessel tone. It also contributes to the maintenance of water-salt homeostasis (constancy) by stimulating the secretion of aldosterone.

In the renin-angiotensin system, the presence of additional peptide fragments, whose function is contradictory and complementary, has also been described. Peptide fragments of angiotensin II are formed under the influence of neutral endopeptidase, aminopeptidase A, B, N and other enzymes.

Angiotensin II is directly involved in left ventricular hypertrophy associated with arterial hypertension. With the help of feedback mechanisms, angiotensin II blocks the release of renin. In a small group of patients, the phenomenon of so-called "reactivation" of angiotensin is observed, during which, despite long-term treatment with AGE-inhibitors, chronic heart failure is observed, which increases the risk of mortality.

When should we do the research?

Determination of angiotensin II together with the renin index is important for the classification of arterial hypertension.

Preparation of the patient: The study is conducted on an empty stomach. The blood sample is taken while the patient is lying down (30 minutes before blood sampling, he should be horizontal).

Interpretation of results

Taking diuretics, mineralocorticoids, glucocorticoids, estrogens, oral contraceptives, mineral-containing preparations affects the measured indicators. It is not recommended to take radioactive drugs within 24 hours before taking the sample.

Reference norms  ​​- 20-40 ng/l

angiotensin II The results of the study are not considered in isolation, but in context with data from other studies.