Manitoba Nephrology Nurse Practice Test

What hormone is released by kidneys in response to low blood pressure?

1. Erythropoietin

2. Renin

3. ADH

4. Aldosterone

The correct answer is: Renin

The correct answer is renin. When blood pressure drops, the kidneys respond by releasing renin, an enzyme that plays a crucial role in the regulation of blood pressure. Renin acts on angiotensinogen, a protein produced by the liver, to convert it into angiotensin I. This conversion is the first step in a cascade of events known as the renin-angiotensin-aldosterone system (RAAS), which ultimately leads to an increase in blood pressure. Angiotensin I is further converted into angiotensin II, a potent vasoconstrictor that increases blood pressure by narrowing blood vessels. Additionally, angiotensin II stimulates the secretion of aldosterone, which promotes sodium and water retention, further assisting in raising blood pressure. While erythropoietin is a hormone released by the kidneys, it primarily signals the bone marrow to produce red blood cells in response to low oxygen levels rather than low blood pressure. ADH (antidiuretic hormone) is released by the posterior pituitary gland in response to high plasma osmolality and low blood volume but is not the initial hormone released in direct response to low blood pressure. Aldosterone, on the other hand, is a hormone that helps retain sodium and