Hormones and Behavior

The pituitary's two separate parts are essential to the production of many hormones but their function in relation to the hypothalamus and endocrine system vary greatly (LeDoux, 1996). The posterior pituitary is an extension of the brain and secretes two types of hormones, oxytocin and antidiuretic hormone (ADH), both of which are produced by the hypothalamus and released into the posterior pituitary. Neurosecretory cells in the hypothalamus produce oxytocin and ADH and are transported down an axon to the posterior pituitary where it is stored (LeDoux, 1996). The posterior pituitary releases these hormones when needed via the bloodstream to bind to their target cells. The posterior pituitary's hormones elicit specific responses from the kidneys, by means of ADH, and the mammary glands, by means of oxytocin (LeDoux, 1996). ADH acts directly on the ability of the kidneys to reabsorb water, whereas oxytocin causes mammary glands to release milk (LeDoux, 1996).
             The anterior pituitary also relies on the hypothalamus to control and regulate its hormonal release, but in a less direct manner. Neurosecretory cells located in the hypothalamus drive the release of hormones by the anterior pituitary (LeDoux, 1996). When the hypothalamus receives a signal for the need of a hormone produced by the anterior pituitary, it sends releasing hormones through short portal vessels and into a second capillary network within the anterior pituitary, where it acts on a specific hormone (LeDoux, 1996). Besides releasing stimulatory hormones the hypothalamus also releases inhibiting hormones, which prevent the release of certain hormones from the anterior pituitary. The anterior pituitary produces and releases several different hormones with many different functions. Its hormones range from growth hormones that act on bones, to prolactin, which stimulates mammary glands (LeDoux, 1996). A unique function of those hormones released by the anterior pituitary, is that some of them act on other endocrine glands and signal them to produce and release other hormones (LeDoux, 1996).