What is a primary function of angiotensin II?

Angiotensin II plays a critical role in regulating blood pressure and fluid balance in the body. One of its primary functions is to constrict arterioles, which leads to an increase in total peripheral resistance; this directly raises blood pressure. This vasoconstriction occurs primarily in the small arteries and arterioles, making them narrower and forcing the blood to exert more pressure against the vessel walls.

Additionally, angiotensin II stimulates the release of aldosterone from the adrenal glands, which promotes sodium retention in the kidneys and further aids in increasing blood volume, thereby contributing to an increase in blood pressure. This makes angiotensin II a vital component of the renin-angiotensin-aldosterone system (RAAS), which is essential for maintaining cardiovascular health and fluid homeostasis.