Renin is an enzyme produced and secreted by specialized cells in the kidneys, known as juxtaglomerular cells. It plays a crucial role in regulating blood pressure and maintaining fluid and electrolyte balance in the body. Renin acts on a protein called angiotensinogen, which is released by the liver into the bloodstream, and converts it into angiotensin I.
Angiotensin I is subsequently converted into angiotensin II by another enzyme called angiotensin-converting enzyme (ACE), found primarily in the lungs. Angiotensin II is a potent vasoconstrictor, meaning it narrows the blood vessels, leading to an increase in blood pressure. It also stimulates the release of aldosterone, a hormone that helps regulate sodium and water reabsorption by the kidneys.
The release of renin is influenced by various factors, including low blood pressure, low blood volume, decreased sodium levels, and sympathetic nervous system activity. Renin release is part of a complex feedback loop that helps maintain blood pressure within a normal range.
In some medical conditions, such as certain forms of hypertension or kidney diseases, the renin-angiotensin-aldosterone system may be dysregulated, resulting in abnormal blood pressure regulation. Renin inhibitors, a class of medications, can be used to block the action of renin and reduce blood pressure in such cases.
