The purpose of the study is to evaluate the effects of growth hormone replacement on women with growth hormone deficiency. Growth hormone deficiency means the body no longer produces growth hormone due to a tumor or some kind of disease of the brain in an area called the pituitary/hypothalamic region. This is the area of the brain where growth hormone is normally produced. We, the researchers at Massachusetts General Hospital, will establish the effects of growth hormone replacement on cardiovascular parameters (laboratory tests, the flexibility of the arteries, changes in heart rate) in women with growth hormone deficiency. Our goal is to see if this therapy: