Mechanism of antidiuretic hormone-induced hyponatremia

The mechanisms by which antidiuretic hormone (ADH) causes hyponatremia mainly involve three aspects: First, ADH reduces sodium excretion in the renal tubules, thereby decreasing the sodium concentration in the blood. Second, ADH inhibits water excretion from the renal tubules, leading to reduced plasma osmolality and fluid loss, which subsequently lowers serum sodium levels. Third, ADH increases potassium excretion in the renal tubules, which also contributes to decreased blood sodium concentration. The primary mechanisms by which ADH induces hyponatremia are reduced sodium excretion, reduced water excretion, and increased potassium excretion in the renal tubules. These three mechanisms are the main causes of ADH-induced hyponatremia.