ATI Pathophysiology Practice Exam

Which hormone produced by the kidneys is involved in fluid balance?

1. Aldosterone

2. Renin

3. Thyroxine

4. Insulin

The correct answer is: Renin

Renin is a hormone produced by the kidneys that plays a crucial role in the regulation of blood pressure and fluid balance. It is released in response to low blood pressure, decreased sodium chloride concentration, or sympathetic nervous system stimulation. Renin initiates the renin-angiotensin-aldosterone system (RAAS) by converting angiotensinogen, produced by the liver, into angiotensin I. This, in turn, is converted to angiotensin II, which helps increase blood pressure through vasoconstriction and stimulates the secretion of aldosterone from the adrenal glands. Aldosterone promotes sodium retention in the kidneys, which leads to increased water retention and helps maintain fluid balance in the body. While aldosterone is directly involved in fluid balance, it is the initial role of renin in activating this cascade that makes it significant in the regulation of fluid balance. Thyroxine and insulin do not have direct roles in fluid balance; thyroxine primarily regulates metabolism, and insulin is involved in glucose metabolism.