Definition Of Angiotensin

Angiotensin plays a vital role in regulating and maintaining the level of blood pressure in the bloodstream and also affects the fluidity level in the body. There are other hormones that increase and decrease the production of angiotensin hormone in the body. 

Overview

Angiotensin is a chemical compound found in the body. It comes under the category of protein hormones that help blood vessels taper or become narrower. It also supports regulating and maintaining the level of blood pressure and balances the fluidity in the body. 

In other words, a peptide chain, angiotensin, which has formed angiotensin II, helps in the contraction of blood vessels. This hormone is represented by Roman numbers as angiotensin I–IV. The action of angiotensin and its activation form in the body together are known as the renin-angiotensin system. 

Forms of Angiotensin

There are three forms of angiotensin: 

Angiotensin I, the production of this is caused by the action of renin on a protein known as angiotensinogen. Through the direct action of angiotensin-converting enzyme (ACE) on Angiotensin I, it converts into Angiotensin II. Angiotensin II directly works on blood vessels which lead to increased blood pressure. Angiotensin III is also a product of angiotensin II and behaves similarly but with less effectiveness. 

The Role of Renin

The site of secretion and release of this protein hormone is the liver. Then, it is further broken down into simpler molecules by an enzyme called renin. Renin is secreted in the kidney for the formation of angiotensin I. Renin does not have any specific biological function to perform but plays a vital role as a precursor for angiotensin hormone II. After secretion in the kidney, renin flows through blood vessels by the lungs and kidneys and leads to other metabolic activities to manufacture angiotensin II with the help of enzyme angiotensin-converting enzyme. 

Functions of Angiotensin II

The main purpose of angiotensin II is to maintain the blood pressure level, body fluids and sodium content. The following are the main functions of angiotensin II: 

Blood vessels

By reducing the size of blood vessels, it improves the blood pressure level. 

Nerves 

It helps maintain the osmosis fluid amount in the body. It acts upon the body to increase the thirst, desire for salt, and support the secretion of other hormones that have a tendency to retain the fluid content. 

Adrenal glands

In addition to stimulating the production of the aldosterone hormone,  angiotensin also helps maintain sodium and potassium in the kidneys. 

Kidneys

In the kidneys, angiotensin helps retain the sodium content and affects the functioning of the kidneys. It also helps enhance water reabsorption in the kidneys to increase the blood amount and blood pressure.

Regulation of Angiotensin

There is a direct relationship between the production of renin and reduced sodium content and blood pressure due to the nerve-automated system of kidneys. This system of renin-angiotensin is also dependent on other hormones, such as corticosteroids, oestrogen, and thyroid hormones. However, natriuretic peptides have the capacity to inhibit the functioning of the renin-angiotensin system, which causes enhancement of sodium loss in the urine. 

Angiotensin-Converting Enzyme (ACE)

Generally, angiotensin-converting enzyme (ACE) chemical compounds (drugs or medicines) are prescribed by doctors for high blood pressure patients and other heart-related problems. These medications help lower blood pressure in the veins and arteries. This inhibits the functioning of an enzyme that directly supports the production of angiotensin II. Examples of ACE inhibitors include Fosinopril, Benazepril (Lotensin), Captopril, Enalapril (Vasotec), etc. 

ACE inhibitors are utilised to treat the following signs and symptoms: 

• High blood pressure (hypertension)
• Coronary artery disease
• Heart failure
• Diabetes
• Certain chronic kidney diseases
• Heart attacks
• Migraines

Conclusion

Therefore, the level of angiotensin can be reduced or induced through medications and drugs. There is a direct relationship between the production of renin and reduced level of sodium content and blood pressure due to the nerve-automated system of kidneys. This system of renin-angiotensin is also dependent on other hormones, such as corticosteroids, oestrogen, and thyroid hormones. On the contrary, natriuretic peptides have the capacity to inhibit the functioning of the renin-angiotensin system, which causes enhancement of sodium loss in the urine. Nevertheless, it plays a vital role in regulating and maintaining the blood pressure level in the bloodstream and affects the fluidity level in the body.