1. To diagnose central adrenal deficiency, patients not on glucocorticoid replacement will have an insulin tolerance test (ITT) (patients with cardiovascular disease will be excluded) in which 0.1U/kg of insulin will be given by iv and a peak cortisol value of less than 20ug/dl, associated with a glucose level of less than 40mg/dL will be considered consistent with central adrenal insufficiency. Patients on glucocorticoid replacement will be evaluated by examining their prior workup and if it is determined that they had evidence of central adrenal deficiency, an ITT will not be required to document central adrenal deficiency (an ITT will still be performed to determine GH deficiency).