Optometry Admission Test (OAT) Practice

What regulates the secretion of aldosterone?

1. Neural signals

2. Renin-angiotensin system

3. Electrolyte levels

4. Glucose levels

The correct answer is: Renin-angiotensin system

The secretion of aldosterone is primarily regulated by the renin-angiotensin system. Aldosterone, a hormone produced by the adrenal cortex, plays a crucial role in regulating sodium and potassium balance as well as blood pressure. When blood pressure drops or sodium levels decrease, specialized cells in the kidneys release renin. Renin then converts angiotensinogen, produced by the liver, into angiotensin I, which is subsequently converted into angiotensin II by the action of ACE (angiotensin-converting enzyme) primarily in the lungs. Angiotensin II has several effects, one of which is stimulating the adrenal glands to secrete aldosterone. The increase in aldosterone leads to the reabsorption of sodium in the kidneys, which, in turn, helps increase blood volume and blood pressure. While neural signals and electrolyte levels can influence aldosterone secretion, particularly through the sympathetic nervous system and changes in potassium levels, they are not the primary regulatory mechanisms. Glucose levels hold little relevance in the direct regulation of aldosterone secretion, further supporting the renin-angiotensin system's role as the main controller of this hormone's activity.