American Board of Pathology (ABPath) Practice Test 2025 - Free Pathology Exam Practice Questions and Study Guide

Aldosterone is a steroid hormone produced by the adrenal cortex that plays a crucial role in regulating salt and water balance in the body. It primarily acts on the kidneys, promoting the reabsorption of sodium and water while facilitating the excretion of potassium. This mechanism leads to increased sodium (and consequently water) retention, which can result in edema (the accumulation of fluid in tissues) and contributes to feelings of fatigue due to the physiological changes that occur with fluid retention.

In conditions where aldosterone levels are elevated, such as primary hyperaldosteronism (Conn's syndrome), sodium retention becomes pronounced, leading to other associated symptoms such as hypertension and weakened muscle function, further contributing to fatigue. Understanding the role of aldosterone in fluid balance helps clarify its connection to the symptoms listed in the question.

Other hormones mentioned have different roles: insulin primarily regulates glucose metabolism, cortisol influences metabolism and stress response without directly causing sodium retention, and glucagon primarily works to increase blood glucose levels by promoting gluconeogenesis and glycogenolysis. Therefore, aldosterone stands out as the hormone directly related to sodium retention, edema, and fatigue.