The study is designed as an open labeled pilot trial to analyze the acute responses of glucose, GLP-1, GIP, insulin secretory,and glucagon to a mixed meal tolerance test (MMTT) or intravenous glucose tolerance tests (IVGTT) with and without pretreatment with Exenatide (Byetta) 5 mcg sc.

The investigators will also test the effects of Exenatide on gastric emptying during the MMTT.

Inclusion Criteria:

• T1D of at least 3 yrs duration.
• Male or female aged 18-56 years who meets the American Diabetes Association standard T1DM criteria.
• HgbA1c<9%
• Insulin requirement of < 0.8 U/kg/d
• Absence of severe hypoglycemia in the past 6 months
• Absence of ketoacidosis in the past 6 months
• Menstruating women must have a negative pregnancy test and be willing to avoid pregnancy during the study period.
• Signed informed consent..

Exclusion Criteria:

• Inability or unwillingness to give informed consent.
• Prior Exenatide or Liraglutide treatment or use of any medication that could potentially affect diabetes or immunologic status
• Known hypersensitivity to Exenatide or any product components
• Participation in an investigational treatment trial within the last 6 weeks before enrollment.
• Any medical condition that in the opinion of the investigator would interfere with safe completion of the trial such as: epilepsy, atopic disease, active Grave's disease, cystic fibrosis, sickle cell anemia, neuropathy, peripheral vascular disease, cerebrovascular disease,liver disease, HIV, or any concurrent autoimmune disease except treated and stable thyroid disease
• Known severe renal impairment, end-stage renal disease or renal transplantation.
• Any history of gastroparesis or other severe gastrointestinal disease, pancreatitis, thyroid nodules or malignancy with the exclusion of a history of localized basal cell carcinoma.
• Uncompensated heart failure, fluid overload, myocardial infarction or liver disease within the last 6 weeks before enrollment.
• Active clinically serious infections.
• Positive pregnancy test in menstruating women or lactating females