Fig. 3.

Ectopic expression of active XBP1 (XBP1s) in ER stress-experiencing islets enhances GLP-1R signaling use of Gs. (A-D) Isolated mouse islets were infected with adenovirus expressing red fluorescent protein (Ad-RFP) or XBP1s (Ad-XBP1s) and then pretreated with tunicamycin (8 hours) before introducing indicated reagents for 1 hour. The concentrations of reagents were the same as in previous experiments. (A, C) Islets’ insulin secretion and (B, D) its fold change. Data are presented as means ± SEM (n = 4). Statistical analyses were performed using either 1-way ANOVA (A, C) or unpaired t-tests (B, D). *P < .05, **P < .01, ***P < .001.