Role of Exenatide in NASH-a Pilot Study

Inclusion Criteria: * Well documented NASH based on clinical and histological criteria. Liver biopsy must have been obtained within 12-months prior to initiation of the study. * Subjects must have known diabetes (either diet controlled or only on Metformin or sulfonylureas such as glyburide or glipizide). * Subjects must be 18 year or older. Exclusion Criteria: * Co-existing etiologies for chronic liver disease (hepatitis B or C, autoimmune or hemochromatosis, etc.). * Clinical or histological evidence of cirrhosis. * Alanine aminotransferase or aspartate aminotransferase \> 300 IU/L. * Uncontrolled diabetes (hemoglobin A1C greater than or equal to 9%). * Insulin or TZD dependant DM. * Known human immunodeficiency virus infection. * Current or history of significant alcohol consumption within past 5 years. Significant alcohol consumption is defined as \>20 grm/day in females and \>30 grms/day in males or if alcohol consumption cannot satisfactorily be quantified. * Serum creatinine of greater than or equal to 2 mg/dl. * Active, serious medical disease (cardiac, renal, pulmonary, dermatologic, psychiatric illness) with likely life expectancy less 5 years. * Current or previous malignancy with expected life expectancy less than 5-years (other than basal cell cancer of the skin). * Use of drugs historically associated with NASH. * Histological evidence of malignancy, 4+ iron deposition, or any other type of liver disease. * Active substance abuse, such as alcohol,inhaled or injection drugs with the previous one year. * Known intolerance or allergy to exenatide (Byetta). * History of neuroglycopenia. * Women of childbearing potential must have had a negative pregnancy test prior to starting the study and should be willing to avoid pregnancy during the study period. * Women must not be nursing.