Question

A person with kidney disease may develop hypertension. What are two different mechanisms by which abnormal kidney function might produce hypertension? What are two different ways that drugs could act via the kidneys to reduce hypertension?

Answer 1

Kidney increases the blood pressure via release of Renin that causes conversion of angiotensinogen to angiotensin I and then Angiotensin II is formed from angiotensin I by Angiotensin Converting Enzyme . This acts on the afferent arteriole causing vasoconstriction and other body vessels to cause vasoconstriction, both leads to increase blood pressure.

Here, action of Angiotensin II can be prevented by preventing its formation by inhibiting the enzyme Angiotensin Converting ENZYME (ACE inhibitors). Also Angiotensin Receptor Blockers (ARBs) can be used to prevent the action of angiotensin II that helps to reduce blood pressure.

Kidney Also causes retention of the fluid and prevent loss of water into the urine. This decreases the urine formation and increases blood volume leading to hypertension.

Hence diuretics are used that increases the filtration and fluid loss and thus reduces blood volume and blood pressure.