Adult Growth Hormone Deficiency and Cardiovascular Risk

Assessment of Cardiovascular Risk Markers in GH Deficient Patients With Nonsecreting Pituitary Adenomas

This protocol will assess the cardiovascular risk associated with growth hormone deficiency in adults. We will use multiple modalities to assess risk for heart attacks or strokes including blood work, ultrasound, MRI and endothelial cell biopsies in both patients who are growth hormone deficient and in patients with normal growth hormone secretion. We hypothesize that adults with growth hormone deficiency will have results suggestive of an increased risk for cardiovascular disease.

Subjects will first be tested for possible growth hormone deficiency. This will be done by administering two intravenous medications that should stimulate growth hormone secretion and we will measure growth hormone in the blood every 30 minutes following the administration. Once we have the results on enough subjects we will split the cohort into those subjects who are growth hormone deficient and those who have normal growth hormone. The two groups will each undergo various tests all designed to assess some component of cardiovascular risk. Ultimately we will compare the results of each test to see if those who are growth hormone deficient have an increased risk for cardiovascular disease.

Patients who have undergone transsphenoidal surgery for a pituitary adenoma and have normal growth hormone secretion: Subjects will undergo a clinical exam with vital signs and blood draws, anthropometric measurements and skin fold thickness assessments. Subjects will also undergo GH stimulation testing with growth hormone releasing hormone (GHRH) & arginine, MRI and MR spectroscopy, carotid ultrasound, and have an endothelial cell biopsy.

Patients who have undergone transsphenoidal surgery for pituitary adenoma who are growth hormone deficient: Subjects will undergo a clinical exam with vital signs and blood draws, anthropometric measurements and skin fold thickness assessments. Subjects will also undergo GH stimulation testing with growth hormone releasing hormone (GHRH) & arginine, MRI and MR spectroscopy, carotid ultrasound, and have an endothelial cell biopsy.

Subjects will receive GHRH and arginine intravenously and then have blood drawn at frequent intervals over a 90 minutes to assess growth hormone secretion.

Subjects will have an ultrasound of their neck to assess their carotid arteries to look for intima-medial thickness.

Subjects will have MRI and MR spectroscopy of the abdomen and lower extremities to assess for fat in internal organs and muscle.

Subjects will undergo endothelial cell biopsies to harvest endothelial cells to study. It will occur once and takes approximately 20 minutes. Patients will have an iv placed and then a sterile wire is passed back and forth in the iv a couple of times. Three wires are passed.

Endothelial function as assessed by flow mediated dilatation and endothelial cell biopsy for measurement of inflammatory markers.

Inclusion Criteria: Adults 19 years or older who have undergone transsphenoidal surgery for a clinically non-secreting pituitary adenoma Exclusion Criteria: Currently taking growth hormone, radiation therapy in the past 5 years, changes in dose of other pituitary hormone replacement therapy in past 3 months, taking hydrocortisone (or its equivalent) at a dose of > 30 mg/day, pregnant or nursing women