Which hormone is responsible for increasing sodium retention in the kidneys?

Aldosterone is a steroid hormone produced by the adrenal cortex that plays a crucial role in regulating sodium and water balance in the body. Its primary action is to enhance sodium reabsorption in the kidneys, specifically in the distal convoluted tubules and collecting ducts. When aldosterone is secreted, it promotes the insertion of sodium channels and sodium-potassium pumps in the renal tubular cells. This leads to increased retention of sodium in the bloodstream, which helps to regulate blood pressure and fluid balance.

In addition to its role in sodium retention, aldosterone also facilitates the excretion of potassium. The retention of sodium causes water to follow osmotically, contributing to increased blood volume and, consequently, increased blood pressure. This hormone is also part of the renin-angiotensin-aldosterone system (RAAS), which is activated in response to low blood pressure, low blood volume, or low sodium levels.

The other hormones listed, while they have important roles in the body, do not primarily focus on sodium retention in the kidneys. Cortisol also plays a role in regulating metabolism and immune response but is not primarily involved in sodium retention. Epinephrine and norepinephrine are primarily involved in the fight-or-flight response, affecting heart