The Short- and Long-Term Effect of Liraglutide on the Beta Cell Function in Type 2 Diabetic Patients

Glucagon-like peptide 1 (GLP-1) is a hormone, inducing glucose-dependent stimulation of insulin secretion from beta cells. Liraglutide acts as a GLP-1 receptor agonist. To assess the effect of liraglutide on the beta cell function, we performed oral glucose tolerance tests in 7 subjects with type 2 diabetes before and after treatment of liraglutide. Moreover, we performed same study again in 4 subjects at 6 months after induction. Liraglutide significantly increased area under the Curve (AUC) of plasma insulin level after glucose loading and significantly decreased AUC of plasma glucose level, compared with before induction. HOMA-beta was significantly increased, whereas insulinogenic index was not changed. HOMA-R was not affected but Matsuda index was significantly decreased after induction of liraglutide. Disposition index was not altered significantly, but tendency of improvement was observed. Glucose tolerance tests revealed that those effects of liraglutide were continued for 6 months after induction. These results showed that treatment of liraglutide could improve insulin secretion but early phase of insulin secretion was not improved. The results suggest that liraglutide is likely to improve beta-cell function, but this effect is still inadequate by six-month treatment.