Phase II: Beginning at noon on a different day, patients with any abnormal endocrine tests during phase I undergo 24 hour inpatient dynamic testing of the neuroendocrine system. Patients undergo GH stimulation testing comprised of measurement of serum GH levels before and on 4 occasions during the 2 hours after receiving levodopa. Patients also undergo concurrent thyrotropin releasing hormone (TRH) and gonadotropin releasing hormone (GnRH) stimulation testing comprised of measurement of serum TSH and luteinizing hormone (LH) levels before and at 15, 30, 60, and 90 minutes after receiving TRH and GnRH IV. Patients then undergo overnight metyrapone testing comprised of baseline measurement of serum 11-deoxycortisol and cortisol levels, followed by oral metyrapone with a snack, overnight fasting, and then remeasurement of serum 11-deoxycortisol and cortisol levels.