Effects of Growth Hormone Administration on Cardiovascular Risk in Cured Acromegalics With Growth Hormone Deficiency

The purpose of the study is to evaluate the effects of growth hormone (GH) replacement in men and women with a history of acromegaly and who are now growth hormone deficient. We will compare them to persons with a history of acromegaly who have normal GH levels. Acromegaly results when an area in the brain, called the pituitary, produces too much growth hormone. When an individual is cured of acromegaly, the growth hormone levels may be normal or low (that is GH deficiency). Growth hormone deficiency means the body no longer produces as much growth hormone because the pituitary/hypothalamic region was damaged by a tumor or by treatment received. We will study the effects of growth hormone replacement on the health of the heart and blood vessels of GH deficient persons by looking to see if this therapy: 1. has effects on cardiovascular risk markers (special blood tests which indicate how healthy your heart and arteries are) 2. affects the stiffness of the arteries 3. affects your heart rate and the capacity of your heart to respond to changes in body position 4. has different effects depending on whether you are taking estrogen / testosterone. We will assess these measures of health on one occasion in persons with cured acromegaly and normal GH levels and in persons with cured acromegaly who have GH deficiency and a contraindication to receiving GH. GH deficient individuals with no contraindication to receiving GH, will participate in the study for 12 months. Individuals with normal GH levels, or who are GH deficient and have a contraindication to receiving GH, will be asked to return for one more visit (without any interventions).