The purpose of this study is to investigate and evaluate the effects of different interventions (1. exenatide, 2. insulin, 3. thiazolidinedione) on glycemic control and β-cell function in newly diagnosed drug-naïve type 2 diabetic patients.

One of the fundamental defects in type 2 diabetes mellitus is declining β-cell function. Exenatide targets multiple metabolic disturbances in type 2 diabetes and exerts direct effects on β-cell, which indicates that it may not only contribute to the glucose control but also delay disease progression. There are trials demonstrated efficacy, safety and tolerability of exenatide. However, no study has compared the effects of exenatide with other hypoglycemic therapies with β cell protective function in newly diagnosed and drug-naïve type 2 diabetic patients. This current study is thus designed to evaluate the effects of exenatide, insulin and pioglitazone on glycemic control and β-cell function in newly diagnosed drug-naïve type 2 diabetic patients.

Inclusion Criteria:

• newly-diagnosed type 2 diabetic patients, drug naïve
• age 30~70 years
• HbA1c 7.0~10.0%
• BMI 20~35 kg/m2, stable body weight (≤10% variation) for at least 3 months prior to screening
• female patients of reproductive age should practice a reliable method of birth control throughout the study

Exclusion Criteria:

• acute or severe chronic diabetic complications
• congestive heart failure (NYHA grade Ⅲ~Ⅳ)
• severe gastrointestinal disease
• severe osteoporosis or history of pathological fracture,or use of bisphosphonates preparation
• other severe intercurrent illness
• serum aminotransferase (ALT and AST) level higher than 2 times of the upper normal limits and/or serum creatinie≥133µmol/L (1.5mg/dL)
• tested positive for glutamic acid decarboxylase antibody
• use of weight loss drugs, corticosteroids, drugs known to affect gastrointestinal motility, transplantation medications, or any investigational drug
• history of pancreatitis
• serum triglyceride ≥ 5.0 mmol/L
• pregnancy