Which hormone is critical for regulating blood pressure and fluid balance?

Aldosterone plays a crucial role in regulating blood pressure and fluid balance within the body. It is a steroid hormone produced by the adrenal glands and is part of the renin-angiotensin-aldosterone system (RAAS). When blood pressure drops or when there is a decrease in sodium levels, the adrenal glands release aldosterone. This hormone acts primarily on the kidneys, where it promotes the reabsorption of sodium and water back into the bloodstream. By increasing sodium reabsorption, aldosterone also enhances water retention, which increases blood volume and, consequently, blood pressure.

Additionally, aldosterone stimulates the excretion of potassium, which assists in maintaining electrolyte balance. Through these mechanisms, aldosterone is instrumental in ensuring that blood pressure is maintained within a normal range and that fluid balance in the body is appropriately regulated, preventing conditions such as dehydration or excessive fluid retention.