Optometry Admission Test (OAT) Practice

Where is vasopressin stored in the body?

1. The anterior pituitary

2. The pancreas

3. The posterior pituitary

4. The thyroid gland

The correct answer is: The posterior pituitary

Vasopressin, also known as antidiuretic hormone (ADH), is synthesized in the hypothalamus and then transported down the axons to the posterior pituitary gland, where it is stored and released into the bloodstream as needed. This location is crucial because the posterior pituitary acts as a reservoir for vasopressin, allowing for its rapid release in response to physiological signals, such as increased plasma osmolality or low blood volume. The role of vasopressin is essential in regulating water balance in the body by influencing kidney function. When vasopressin is released, it promotes water reabsorption in the kidneys, thereby decreasing urine output and helping to control hydration status. The other options do not serve as storage sites for vasopressin. The anterior pituitary produces different hormones primarily associated with growth and reproduction, the pancreas is involved in regulating blood glucose levels with hormones like insulin and glucagon, and the thyroid gland produces hormones that regulate metabolism. Thus, the posterior pituitary is specifically responsible for the storage and release of vasopressin.