Figure 2. Pancreatic β cell insufficiency secondary to loss of InsP3R, impaired oral glucose tolerance, and insulin secretion deficits in 3-month-old Ankb^{R1788W/R1788W} mice.

(A) InsP3R and GAPDH protein levels in isolated pancreatic islets of 3-month-old mice. (B) Insulin secretion by cultured pancreatic islets in response to glucose. Data represent mean ± SEM (n = 7 mice, ***P < 0.001, 1-way ANOVA with post-hoc Tukey test). (C) Serum insulin levels in Ankb^+/+, Ankb^{L1622I/L1622I}, and Ankb^{R1788W/R1788W} mice 30 minutes after oral glucose administration during an oral glucose tolerance test (OGTT). (D) Blood glucose levels in response to oral glucose (2 mg/kg body weight) for the indicated genotypes. (E) Area under the curve for the OGTT. (F) Blood glucose levels in response to oral glucose (2 mg/kg body weight) for 3-month-old control (Itpr1^+/+) and Itpr1^+/– mice. (G) Area under the curve for the OGTT. (H) Serum insulin levels 30 minutes after oral glucose administration during an OGTT for control and Itpr1^+/– mice. Data from C–H represent mean ± SEM (n = 10 mice.) **P < 0.01, ***P < 0.001, 1-way ANOVA with post-hoc Tukey test. Results are representative of 3 independent experiments.