The Effects of Bariatric Surgeries on Glucose Metabolism

Eligibility Details: Inclusion Criteria: - Hypoglycemic RYGB patients with documented blood glucose level <50 mg/dl - Asymptomatic individuals with bariatric surgery - Healthy non-surgical patients with no personal history of diabetes - Subjects must physically be able to come to our clinical research center Cedars-Sinai Medical Center Exclusion Criteria: - Active heart, lung, liver, gastrointestinal or kidney disease; unable to give informed consent; pregnancy; uncontrolled high blood pressure or high cholesterol; significant anemia (hemoglobin <11g/dL); prisoners or institutionalized individuals; type 2 diabetes mellitis; development of any serious medical or psychiatric illness during recruitment or studies; - RYGB patients will be disqualified if they have gastric outlet obstruction or severe diarrhea. - Healthy non-surgical patients with personal history of diabetes For administration of atropine, the following exclusions also apply: - History of glaucoma - Uncontrolled hypertension (any subjects with BP>140/90 and history of dyslipidemia - Taking any medication that might interact with atropine and cannot be stopped will be excluded from the study) - Myasthenia gravis - Brain pathology - Enlarged prostate in men