Angiotensin Peptides and Blood Pressure
Medically reviewed by Dr. Sarah Chen, PharmD, BCPS
Angiotensin peptides are key components of the renin-angiotensin system, which plays a critical role in the regulation of blood pressure.
The Renin-Angiotensin System (RAS)
The renin-angiotensin system (RAS) is a hormonal cascade that plays a crucial role in regulating blood pressure and fluid balance. The system is initiated by the release of renin from the kidneys in response to low blood pressure or low sodium levels. Renin then cleaves angiotensinogen, a protein produced by the liver, to form angiotensin I. Angiotensin I is then converted to angiotensin II by angiotensin-converting enzyme (ACE), which is primarily found in the lungs.
Angiotensin II: The Main Effector Peptide
Angiotensin II is the main effector peptide of the RAS. It is a potent vasoconstrictor, meaning it causes the narrowing of blood vessels, which leads to an increase in blood pressure. Angiotensin II also stimulates the release of aldosterone from the adrenal glands, which promotes the reabsorption of sodium and water by the kidneys, further increasing blood volume and blood pressure. In addition, angiotensin II has other effects, such as stimulating thirst and promoting inflammation.
Therapeutic Targeting of the RAS
The central role of the RAS in blood pressure regulation has made it a major target for the treatment of hypertension (high blood pressure). There are several classes of drugs that target the RAS, including ACE inhibitors, angiotensin II receptor blockers (ARBs), and direct renin inhibitors. ACE inhibitors, such as lisinopril and enalapril, block the conversion of angiotensin I to angiotensin II. ARBs, such as losartan and valsartan, block the binding of angiotensin II to its receptor. Direct renin inhibitors, such as aliskiren, block the first step in the RAS cascade.
Other Angiotensin Peptides
In addition to angiotensin II, there are other angiotensin peptides that have biological activity. Angiotensin-(1-7) is a peptide that has opposing effects to angiotensin II, promoting vasodilation and having anti-inflammatory properties. The balance between angiotensin II and angiotensin-(1-7) is thought to be important for maintaining cardiovascular health. Research is ongoing to explore the therapeutic potential of modulating the activity of these other angiotensin peptides.
| Drug Class | Mechanism of Action | Examples |
|---|---|---|
| ACE Inhibitors | Block the conversion of angiotensin I to angiotensin II | Lisinopril, Enalapril |
| ARBs | Block the binding of angiotensin II to its receptor | Losartan, Valsartan |
| Direct Renin Inhibitors | Block the activity of renin | Aliskiren |
Key Takeaways
The renin-angiotensin system (RAS) is a key regulator of blood pressure.
Angiotensin II is the main effector peptide of the RAS.
Targeting the RAS is a major strategy for treating hypertension.
There are several classes of drugs that target the RAS.
Other angiotensin peptides, such as angiotensin-(1-7), have opposing effects to angiotensin II.
The balance between different angiotensin peptides is important for cardiovascular health.
> Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting any peptide therapy or making changes to your health regimen.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5991823/
[2] https://www.ahajournals.org/doi/10.1161/01.HYP.35.1.162
[3] https://www.sciencedirect.com/topics/neuroscience/renin-angiotensin-system
---