This study is a placebo-controlled study in both healthy normal subjects and patients with Type 2 Diabetes Mellitus to assess the levels of exenatide in the bloodstream when it is given for 7 days, and to assess the impact this medication has on various substances in the blood. Assessments include repeat blood sampling and monitoring of any side effects.

Inclusion Criteria:

• have type 2 diabetes mellitus that has been diagnosed for at least three months
• must be taking either (1) no medication for their diabetes or (2) taking metformin, a sulfonylurea, or metformin and a sulfonylurea
• must be willing to wash-out of these medications for 14 days prior to the start of the study
• must have bloodwork that meets certain criteria (for example, total cholesterol < 240 mg/dL)

Exclusion Criteria:

• must not have any other major illness other than diabetes