Which hormones are involved when the body experiences fluid overload or dehydration?

Atrial natriuretic peptide (ANP) is a key hormone involved in the regulation of fluid balance in the body, particularly in conditions of fluid overload. When the body senses an increase in blood volume or pressure, the heart releases ANP from the atria. This hormone promotes the excretion of sodium and water by the kidneys, leading to increased urine output and consequently reducing blood volume and pressure. This mechanism helps prevent conditions such as hypertension and heart failure that can arise from fluid overload.

In contrast, during dehydration, the body responds by releasing other hormones like antidiuretic hormone (ADH) to conserve water, but ANP specifically works to eliminate excess fluids, showcasing its role in maintaining homeostasis related to fluid balance. Thus, the involvement of ANP in both the response to fluid overload as well as its function in overall fluid regulation makes it the correct choice in this context.