What is angiotensin?

Angiotensin is a hormone that causes vasoconstriction, or the narrowing of blood vessels. It is produced by the kidneys in response to low blood pressure or low blood volume. Angiotensin acts on the smooth muscle of blood vessels, causing them to contract and increase blood pressure. It also stimulates the adrenal glands to release aldosterone, which promotes the retention of sodium and water by the kidneys, further increasing blood pressure.

Angiotensin is part of the renin-angiotensin-aldosterone system (RAAS), a complex hormonal pathway that regulates blood pressure, fluid balance, and electrolyte balance. When blood pressure drops, the kidneys release renin, which converts a protein called angiotensinogen into angiotensin I. Angiotensin I is then converted into angiotensin II by an enzyme called angiotensin-converting enzyme (ACE). Angiotensin II is the active form of the hormone, and it is responsible for causing vasoconstriction and promoting the release of aldosterone.

The RAAS is an important part of the body's blood pressure regulation system. However, excessive activation of the RAAS can lead to high blood pressure (hypertension), a major risk factor for heart disease, stroke, and kidney disease. ACE inhibitors and angiotensin receptor blockers (ARBs) are two types of medications that are used to treat hypertension by blocking the RAAS.