FIG. 6.

Alb-Cre-PTP1B^−/− mice are resistant to HFD-induced ER stress. A and B: Liver lysates from mice fed HFD for 18 weeks were analyzed by immunoblotting for p38 MAPK, JNK, PERK, and eIF2α phosphorylation. Blots were stripped and re-probed with total p38 antibodies. JNK, PERK, and eIF2α levels could not be assessed on re-probes, so the same samples were resolved on a parallel gel and immunoblotted for total levels. All immunoblots were quantified by densitometry (Image J). Bar graphs represent pooled data (% difference from control) from Alb-Cre-PTP1B^−/− and fl/fl mice. C: Expression of CHOP mRNA at 5 and 18 weeks HFD (C) XBP1 at 18 weeks HFD (D) were measured by quantitative real-time PCR and normalized to 18S expression in livers from Alb-Cre-PTP1B^−/− (n = 6) and fl/fl control mice (n = 6). Liver lysates from mice fed HFD for 18 weeks were also analyzed by immunoblotting for total levels of CHOP protein, and these blots are included in C. Results represent the means ± SE, and significance was assessed by two-tailed Student's t test (*P < 0.05, **P < 0.01).