A patient who excretes a large volume of very dilute urine may be experiencing a deficiency in which hormone?

The correct answer is related to the role of antidiuretic hormone (ADH), also known as vasopressin. This hormone is produced in the hypothalamus and stored in the posterior pituitary gland. ADH regulates water balance in the body by influencing the kidneys' ability to concentrate urine.

When ADH is present, it promotes the reabsorption of water in the collecting ducts of the nephron. This process allows the kidneys to produce concentrated urine, thereby reducing urine volume. Conversely, if a patient is excreting a large volume of very dilute urine, it indicates that there is insufficient ADH being released or that the kidneys are not responding properly to it. This condition can lead to excessive urination (polyuria) and can be seen in disorders such as diabetes insipidus.

The other hormones listed—aldosterone, cortisol, and renin—serve different functions within the urinary and endocrine systems. Aldosterone is primarily involved in sodium reabsorption and potassium excretion, which indirectly influences water balance, but its direct effect on urine concentration is not as significant as that of ADH. Cortisol has role in metabolism and stress response but does not directly regulate urine concentration. Renin is an enzyme involved in the