Physiology, Aldosterone

Excerpt

Aldosterone is a mineralocorticoid hormone produced in the zona glomerulosa of the adrenal cortex that influences water and salt regulation in the body. Aldosterone's primary function is to act on the late distal tubule and collecting duct of nephrons in the kidney, favoring sodium and water reabsorption and potassium excretion while also contributing to acid-base balance. To execute these tasks, it influences epithelial sodium channels, sodium-potassium exchange pumps, hydrogen ion ATPases, and bicarbonate-chloride antiporters. Aldosterone affects blood pressure by regulating the sodium gradient in the nephron to either increase or decrease the water reabsorped to contribute to the volume of the extracellular fluid (ECF). This, however, is not to be confused with the effect of anti-diuretic hormone (ADH), also referred to as vasopressin. ADH is often released simultaneously with aldosterone in order to support water reabsorption to the ECF by mobilizing aquaporin channels to the apical (lumen-facing) membrane of principal cells in the collecting tubule. Overall, aldosterone is a key player in the multi-factorial regulation of salt, potassium, blood pressure, and acid-base balance.