The pituitary gland is a very small organ, located at the base of the brain, which produces and releases hormones (signals) that control other organs and body processes. The pituitary gland responds to signals from the hypothalamus. The anterior pituitary gland is the front portion of the pituitary gland, and it secretes hormones that control physiological processes including growth, reproduction, and stress. The posterior pituitary gland is behind the anterior portion and secretes hormones involved with water balance and uterine contractions during labor.