Elucidating Growth Hormone Dynamics at Stages of Progressive Nonalcoholic Fatty Liver Disease

Inclusion criteria: Men 18-70yo * BMI between 25kg/m2 - 40kg/m2. * Hepatitis C antibody and Hepatitis B surface antigen negative. * Meet inclusion criteria for one of Groups 1-3 based on medical history, laboratory criteria, and hepatic fat fraction (1H-MRS) and/or liver biopsy * Group 1: No NAFLD: no history of NAFLD/NASH, hepatic fat fraction \<5% on 1H-MRS, ALT \< 30 U/L. * Group 2: Simple Steatosis: no history of NASH, hepatic fat fraction ≥10% on 1H-MRS, ALT \< 30 U/L. * Group 3: Nonalcoholic Steatohepatitis: Biopsy confirmed NASH within the year prior to study participation, with liver fibrosis stage 2 or 3 on biopsy. Exclusion criteria: * Heavy alcohol use defined as consumption of \> 30mg daily for at least 3 consecutive months over the past 5 years * Type 1 diabetes, any use of insulin, or any use of other anti-diabetes medication except metformin or sulfonylurea. Individuals with Type 2 diabetes that is controlled by diet or by metformin and/or sulfonylurea will be eligible. * Use of any specific pharmacological treatments for NAFLD/NASH except vitamin E within the 3 months before screening visit. * Chronic systemic corticosteroid use in the ≤6 months prior to the baseline visit. * Chronic use of Actigall, methotrexate, amiodarone, or tamoxifen * Known diagnosis of alpha-1 antitrypsin deficiency, Wilson's disease, hemochromatosis, or autoimmune hepatitis * Use of GH or GHRH within the past 6 months * Change in lipid lowering or anti-hypertensive regimen within 2 months of screening * Hemoglobin \< 12.5 g/dL * Severe chronic illness judged by the investigator to present a contraindication to participation * History of hypopituitarism, head irradiation or any other condition known to affect the GH axis. * Use of testosterone or estrogen or progesterone unless physiologic stable testosterone use for at least 1 year prior to study entry * Routine MRI exclusion criteria such as the presence of a pacemaker or cerebral aneurysm clip * Weight loss surgery within 1 year before baseline. Weight loss surgery more than 1 year prior to baseline visit is permissible if no active weight loss (\<10% decrease in weight over past 6 months) * Lack of fluency in English and/or inability to complete the consent process in English. * Judge by the investigator to be inappropriate for the study for other reasons not detailed above.