So ADH affects the permeability of the collecting dusts in our kidneys to water. It increases the amount of water that is absorbed back into the blood vessels. And that means it decreases the amount of water that is released in the urine. It increases the concentration of the solute in our urine that is expelled. Now, this in turn increases the amount of water, the volume of the blood, and that increases the blood pressure. And ADH also increases blood pressure by constricting by pressing down on those blood vessels.