A common cause in adults is a pituitary tumor. Other causes include brain cancers, radiation therapy, and surgery or trauma involving the head or neck. A lack of certain hormones that the pituitary would normally make may cause a number of problems affecting the kidneys, thyroid gland, adrenal glands, reproductive glands, and bone and body composition. Each hormone has a specific function in the body. As a result, replacement therapy is often given to people with hypopituitarism with hormones such as thyroxine, hydrocortisone, desmopressin, testosterone in men, estrogen in women, and growth hormone.
Growth hormone affects many of the tissues in the body, including bone, fat and muscle.
Growth hormone deficiency may be easily recognized in children by short stature or delayed growth. In adult growth hormone deficiency, body composition can be affected. Less muscle, more fat and demineralized bone often represent the body composition changes seen in adult growth hormone deficiency. Additional problems in adults include abnormal blood elevations in fat and cholesterol levels, decreased energy and endurance, reduced ability to exercise, difficulties with concentration and memory and heart disease. It is administered by daily injection under the skin.