What is a primary function of aldosterone in the body?

Aldosterone is a steroid hormone produced by the adrenal cortex, and its primary function is to increase sodium reabsorption in the kidneys. This process occurs mainly in the distal nephron, where aldosterone stimulates the epithelial cells to reabsorb sodium ions from the urine back into the bloodstream. As sodium is reabsorbed, it also promotes the retention of water, which helps to increase blood volume and, consequently, blood pressure.

By increasing sodium reabsorption, aldosterone plays a crucial role in maintaining electrolyte balance and regulating blood pressure within a normal range. This action is significant in managing fluid balance, influencing kidney function, and responding to changes in blood pressure and blood volume.