Fig. 4

DPP-4 inhibitor improved insulin sensitivity and glucose tolerance in SL- or SO-fed db/db mice. The experiments were performed in 16-week-old mice, as shown in Fig. 2 (n = 6–11). a Body weight gain. b Blood glucose levels. *P < 0.05 vs. db/db SL. ^†P < 0.05 vs. db/db SO. c Blood glucose levels during insulin tolerance test (ITT). *P < 0.05 vs. db/db SL. ^†P < 0.05 vs. db/db SO. d Blood glucose levels during oral glucose tolerance test (OGTT). *P < 0.05 vs. db/db SL. ^†P < 0.05 vs. db/db SO. e Serum insulin levels during OGTT. *P < 0.05 vs. db/db SL. ^†P < 0.05 vs. db/db SO