Final answer:
Desmopressin (DDAVP) increases the release of antidiuretic hormone (ADH) from endothelial cells, which helps to conserve body water and regulate urine production.
Step-by-step explanation:
Desmopressin (DDAVP) increases antidiuretic hormone (ADH) release from endothelial cells. ADH, also known as vasopressin, plays a crucial role in maintaining fluid balance by promoting water reabsorption in the kidneys. When released, it prevents the loss of additional fluid in urine, helping to restore blood volume and pressure. Desmopressin is used clinically to treat conditions related to inadequate ADH levels, such as diabetes insipidus and bedwetting. It can also cause vasoconstriction, although its primary function is to conserve body water and regulate urine production.