FIG. 7.

Effect of chemical chaperone treatment on the expression of adaptive UPR genes in islets of db/db mice. Islets isolated from diabetic db/db and age-matched nondiabetic control (cont) mice (12–14 weeks of age) were cultured in the absence (control, white bars; db/db, black bars) or presence (db/db, striped bars) of the chemical chaperone PBA (2.5 mmol/L) for 24 h. Total RNA was extracted, reverse-transcribed, and analyzed by real-time RT-PCR. mRNA levels were expressed as fold-change of the level in control islets. Xbp1 splicing was analyzed and expressed as described in Fig. 3. All results are mean ± SEM. n = 7 in each group. *P < 0.05, **P < 0.01, ***P < 0.001 genotype effect; †P < 0.05, ††P < 0.01 PBA treatment effect in db/db mouse islets.