Biologic and Medical Factors Hypothalamic-Pituitary Abnormalities. There is some question as to whether the typical abnormalities observed in the neurological and hormonal systems of people with eating disorders are results or causes of the disorders. The primary setting of these abnormalities originate in a tiny area of the brain known as the hypothalamus, an area which regulates the pituitary gland, sometimes known as the master gland because of its importance in coordinating the nervous and hormonal systems. Imaging studies of the brains of anorectic patients have found high levels of proteins called corticotropin-releasing factors, which are released during periods of stress and block the substance neuropeptide Y, a powerful appetite stimulant. Such appetite-related chemicals may serve as the biologic links between extreme stressful conditions in a young person's life and the later development of anorexia, although some imaging studies indicate that these abnormalities occur after anorexia has developed.
More work is needed.
The hypothalamic-pituitary system is also responsible for the production of important reproductive hormones that are severely depleted in anorectics, resulting in menstrual cessation. High levels of the male hormone testosterone have also been detected in women with eating disorders. Epstein Barr, the virus that causes mononucleosis has also been associated with the development of anorexia. One theory to explain these links is that antibodies triggered by the organisms may damage the brain in the process of fighting the infection. Antibiotics, immunological therapy, and an experimental vaccine for rheumatic fever may even help treat anorexia in such patients.