Final answer:
Antidiuretic Hormone (ADH) is secreted by the hypothalamus and released from the posterior pituitary gland, targeting the kidneys to promote water reabsorption and thus regulate water balance in the body.
Step-by-step explanation:
The Antidiuretic Hormone (ADH), also known as vasopressin, is secreted by the hypothalamus and then delivered to and released from the posterior pituitary gland. ADH's target tissue is the kidneys, specifically the collecting ducts and tubules. Once in the kidneys, ADH has a significant effect: it makes the collecting ducts permeable to water, which allows the body to retain more water by reabsorbing it from the urine back into the bloodstream. This mechanism is crucial for regulating the body's water balance and, therefore, the concentration of urine.