The hormone responsible for regulating salt and water balance in the body is aldosterone. Aldosterone is produced by the adrenal glands, specifically in the outer section called the adrenal cortex.
Aldosterone stimulates the reabsorption of sodium ions (Na+) from the urine into the bloodstream. This procedure occurs in exchange for potassium ions (K+), which are excreted in the urine. Because sodium is reabsorbed along with water in the nephrons, aldosterone indirectly promotes water reabsorption. This helps to maintain blood volume and prevent dehydration.