Figure 3.

OGTT and ITT in Lep^ob/+/GIP^+/+, Lep^ob/ob/GIP^+/+, Lep^ob/ob/GIP^gfp/gfp male mice. OGTTs and ITTs were performed with Lep^ob/+/GIP^+/+ (white circles and bars), Lep^ob/ob/GIP^+/+ (gray circles and bars), and Lep^ob/ob/GIP^gfp/gfp mice (black circles and bars) in cohort 1 (n = 5–6). OGTTs were performed with 8 week (A, B, C) and 21 week (B, D, E) old mice using 1 g/kg glucose. ITTs were performed with 10 week (G) and 30 week (H) old mice using 1 U/kg and 3 U/kg regular insulin, respectively. The glucose levels during ITTs represent the percentage change from fasting glucose levels. Three Lep^ob/+/GIP^+/+ mice (10 weeks old) exhibited symptoms of severe hypoglycemia 60 min after insulin injection and were rescued by oral glucose administration. Thus, the data of these mice at 90 min during the ITT were excluded. Glucose levels during ITTs were not evaluated in 30 week old Lep^ob/+/GIP^+/+ mice because of severe hypoglycemia. (A, B) Plasma total GIP levels, (C, D) blood glucose levels, and (E, F) plasma insulin levels during the OGTT. (G, H) Glucose levels (%) during ITT. ^#P < 0.05, ^##P < 0.01 vs. Lep^ob/+/GIP^+/+. ^†P < 0.05, ^††P < 0.01, ^††P < 0.01. n.s; not significantly different. Data are mean ± SEM.