angíótensín

Angiotensin is a peptide hormone that plays a crucial role in regulating blood pressure and fluid balance in the body. It is part of the renin-angiotensin-aldosterone system (RAAS), a complex hormonal cascade that influences cardiovascular function. The term angiotensin can refer to several related peptides, but commonly it refers to angiotensin II, which is the most biologically active form.

The production of angiotensin begins when the enzyme renin, released by the kidneys, acts on a protein called angiotensinogen, produced by the liver. This reaction converts angiotensinogen into angiotensin I. Angiotensin I is then further processed by an enzyme called angiotensin-converting enzyme (ACE), primarily found in the lungs and blood vessels, to produce angiotensin II.

Angiotensin II exerts its effects through several mechanisms. It is a potent vasoconstrictor, meaning it narrows blood vessels, which increases peripheral resistance and raises blood pressure. It also stimulates the adrenal glands to release aldosterone, a hormone that promotes sodium and water reabsorption by the kidneys, further contributing to increased blood volume and blood pressure. Furthermore, angiotensin II can stimulate thirst and the release of antidiuretic hormone (ADH), which also helps in retaining water. Dysregulation of the RAAS and excessive angiotensin II activity are implicated in various cardiovascular diseases, including hypertension, heart failure, and kidney disease.