Effect of Liraglutide on Automated Closed-loop Glucose Control in Type 1 Diabetes

Inclusion Criteria: 1. age 18-40 years 2. clinical diagnosis of Type 1 diabetes (T1D) (formal antibody and/or genetic testing will not be required) 3. duration of T1D ≥ 1 year 4. HbA1c ≤ 9 % 5. Treated with CSII for at least 3 months 6. Body weight \> 50 kg (to accommodate phlebotomy) 7. Be in good general health without other medical or psychiatric illnesses that would, in the judgment of the investigator, interfere with subject safety or study conduct Exclusion Criteria: 1. Insulin resistant (defined as requiring \> 1.5 units/kg/day at time of study enrollment) 2. Presence of any medical or psychiatric disorder that may interfere with subject safety or study conduct 3. Use of any medications (besides insulin) known to blood glucose levels, including oral or other systemic glucocorticoid therapy. Inhaled, intranasal, or rectal corticosteroid use is allowed along as not given within 4 weeks of admission to the hospital research unit (HRU). Use of topical glucocorticoids is allowable as long as affected skin area does not overlap with study device sites. Subjects using herbal supplements will be excluded, due to the unknown effects of these supplements on glucose control 4. History of hypoglycemic seizure within last 3 months 5. Anemic (low hematocrit), evidence of renal insufficiency (elevated serum creatinine, BUN) or elevated liver function tests. 6. Female subjects who are pregnant, lactating, or unwilling to be tested for pregnancy 7. History of celiac disease gastroparesis, gastroesophageal reflux disease (GERD), disorder of gastric emptying, or disorder of intestinal motility 8. Taking a medication known to affect gastric motility 9. History of pancreatitis, gallstones, alcoholism or high triglyceride levels 10. Personal or family history of thyroid cancer or multiple endocrine neoplasia type 2 (MEN2) 11. Subjects unable to give consent