What is the main purpose of ADH in the body?

The main purpose of antidiuretic hormone (ADH), also known as vasopressin, is to produce concentrated urine. ADH is secreted by the posterior pituitary gland and plays a critical role in regulating the body's water balance. When the body is dehydrated or experiences high osmolarity in the blood, the release of ADH is stimulated. This hormone acts on the kidneys, specifically the collecting ducts, making them more permeable to water. As a result, more water is reabsorbed back into the bloodstream, leading to the production of urine that is more concentrated. This mechanism helps to conserve water and maintain proper hydration levels in the body.