The purpose of this study is to explore whether the novel therapy of type 2 diabetes, vildagliptin, which inhibits dipeptidyl peptidase-4 (DPP-4), affects glucagon counterregulation during hypoglycemia in insulin-treated patients with type 2 diabetes. Vildagliptin is given, together with the on-going insulin therapy, for one month, whereafter hypoglycemia is induced under standardized conditions, and the glucagon response is determined, and compared to that after a month of placebo treatment.

Vildagliptin is an inhibitor of dipeptidyl peptidase-4 (DPP-4) and inhibits glucagon secretion and stimulates insulin secretion. This improves glycemia in subjects with type 2 diabetes with a very low risk for hypoglycemia. If hypoglycemia nevertheless develops, it is important that vildagliptin under such conditions does not inhibit glucagon secretion, since that would aggravate the hypoglycemia. It was indeed previously demonstrated in type 2 diabetes that vildagliptin dos not inhibit glucagon secretion during hypoglycemia. This study explores whether vildagliptin affects glucagon counterregulation during hypoglycemia in insulin-treated patients of type 2 diabetes. Vildagliptin is given, together with the on-going insulin therapy, for one month, whereafter hypoglycemia is induced under standardized conditions, and the glucagon response is determined, and compared to that after a month of placebo treatment. The hypoglycemia is induced bvy a standardized clamp procedure.

Inclusion Criteria:

• Type 2 diabetes
• Insulin treatment
• Age >18 years
• HbA1c <=8.5%

Exclusion Criteria:

• Pregnancy
• Lactation
• Acute infection
• Liver disease
• Treatment with cortisol