Aldosterone helps regulate sodium and potassium levels in the body. This helps control blood pressure and the balance of fluids and electrolytes in the blood.

The kidney hormone renin normally stimulates the adrenal glands to release aldosterone. High levels of both renin and aldosterone are normally present when the body is trying to conserve fluid and salt (sodium). When a tumor is present, an aldosterone level will be high while a renin level will be low. Usually a renin activity test is done when the aldosterone level is measured.

Other important functions of the kidneys include blood pressure regulation, and the production of erythropoietin, which controls red blood cell production in the bone marrow.

Urinary system parts and their functions:
two kidneys – a pair of purplish-brown organs located below the ribs toward the middle of the back. Their function is to:

remove liquid waste from the blood in the form of urine.

keep a stable balance of salts and other substances in the blood.

produce erythropoietin, a hormone that aids the formation of red blood cells.

epinephrine
When secreted into the bloodstream, it rapidly prepares the body for action in emergency situations. The hormone boosts the supply of oxygen and glucose to the brain and muscles, while suppressing other non-emergency bodily processes (digestion in particular).

It increases heart rate and stroke volume, dilates the pupils, and constricts arterioles in the skin and gut while dilating arterioles in skeletal muscles. It elevates the blood sugar level by increasing catalysis of glycogen to glucose in the liver, and at the same time begins the breakdown of lipids in fat cells. Like some other stress hormones, epinephrine has a suppressive effect on the immune system.[5]

Although epinephrine does not have any psychoactive effects, stress or arousal also releases norepinephrine in the brain. Norepinephrine has similar actions in the body, but is also psychoactive