Which hormone primarily regulates blood pressure?

Aldosterone is a key hormone that primarily regulates blood pressure through its effects on sodium and water balance in the body. It is produced by the adrenal glands and functions by promoting sodium reabsorption in the kidneys. When sodium is reabsorbed, water follows osmotically, leading to an increase in blood volume. This increased blood volume raises blood pressure, making aldosterone an important player in the regulation of hypertension.

In addition to its role in sodium retention, aldosterone also facilitates potassium excretion. Maintaining the right balance of sodium and potassium is crucial for proper cardiovascular function and blood pressure regulation. The renin-angiotensin-aldosterone system (RAAS) is one of the primary mechanisms through which aldosterone is produced, particularly in response to low blood pressure or low blood volume.

Other hormones listed have roles in various bodily functions but do not primarily regulate blood pressure in the same manner. For instance, adrenaline (epinephrine) impacts blood pressure mainly through its effects on heart rate and vascular resistance during stress but is not a primary regulator. Estrogen influences vascular function and may have some effects on blood pressure, especially in the context of the menstrual cycle, but it is not a direct regulator. Thyroxine (T4)