9604670 PADEN The pituitary is often called the master gland of the body because hormones that it releases control the function of other glands. One of these hormones is adrenocorticotrophic hormone (ACTH), which stimulates production of cortisol and other steroid hormones by the adrenal gland. ACTH release is in turn controlled by the brain, which stimulates the pituitary to release ACTH in times of stress or injury. Thus understanding the mechanisms by which the brain controls ACTH release is essential for understanding how stress affects the body. It has been known for many years that the brain stimulates ACTH release in part by releasing hormones itself, but it has been unclear if other control mechanisms also exist. Dr. Paden and others have recently discovered that nerve fibers of unknown origin enter the pituitary gland and appear to contact the cells that make ACTH (called corticotrophs). His current studies will determine where these nerves come from and what type of chemical signals they may employ to affect the activity of corticotrophs. Other experiments will investigate whether or not these nerves respond to stress. Results from these studies may demonstrate the existence of an additional pathway by which the brain can control ACTH release, providing new insights into the mechanisms of the stress response.
