What condition causes the kidneys to release sodium, leading to hypovolemia?

The condition that leads to hypovolemia by causing the kidneys to release sodium is related to the lack of antidiuretic hormone (ADH) production. When ADH is insufficient, the renal tubules are unable to reabsorb water effectively, which results in increased water loss through urine. As water is lost, sodium may also be excreted because the body attempts to maintain a balance between water and electrolytes. The consequent decrease in blood volume contributes to hypovolemia.

In the context of the other options, excess fluid retention does not lead to sodium release; instead, it would typically promote fluid overload. High aldosterone levels typically lead to sodium retention and increased fluid volume, which would contradict hypovolemia. Increased urine concentration usually occurs when water is retained, but in the absence of ADH, urine becomes dilute instead, leading to further losses in fluid volume rather than sodium release in a manner that causes hypovolemia.