Figure 3.

12,13-diHOME enhances cold tolerance and facilitates fatty acid uptake by BAT. (a) Body temperature in mice cold challenged at 4 °C for 90 min after pretreatment with 12,13-diHOME, 12,13-epOME or vehicle. Data are means ± s.e.m.; n = 5 mice per group; *P < 0.05 12,13-diHOME, as compared to vehicle, by analysis of variance (ANOVA) with post hoc Bonferroni test. (b,c) Total V(O₂) consumed and V(CO₂) produced (b) and average respiratory-exchange ratio (RER, c) measurements as measured by Comprehensive Lab Animal Monitoring System (CLAMS) for 1 h of cold (4 °C) in mice acutely treated with 12,13-diHOME or vehicle. Data are means ± s.e.m.; n = 6 mice per group; *P < 0.05 by Student’s t-test. (d) Serum triglycerides in mice fed a high-fat diet and treated with 12,13-diHOME or vehicle for 2 weeks. Data are means ± s.e.m.; n = 6 treated as compared to n = 5 controls; *P < 0.05 by Student’s t-test. (e) Radioactivity per 10 mg of liver, gastrocnemius muscle (Gastroc.), heart, interscapular BAT (iBAT), sWAT and epididymal white adipose tissue (eWAT) from mice treated with vehicle or 12,13-diHOME and then given an oral bolus of ³H-labeled triglyceride. Data are means ± s.e.m.; n = 6 per group; *P < 0.05 by Student’s t-test. (f) Radioactivity per 10 mg of tissues from mice treated with vehicle, norepinephrine (NE) or 12,13-diHOME and then given a bolus of ³H-labeled oleate. Data are means ± s.e.m.; n = 8 per group; *P < 0.05 12,13-diHOME as compared to vehicle by ANOVA with post hoc Bonferroni test. (g) Representative images of luciferase activity in Ucp1^Cre Rosa(stop)Luc mice injected intravenously with luciferin-conjugated fatty acid and 12,13-diHOME or vehicle. Data are representative images at 0 min, 10 min and 55 min. (h) Quantification of luciferase activity in (g). (i) Total luciferase counts from six individual experiments were averaged and plotted as the normalized means ± s.e.m.; n = 6 per group; *P < 0.05 12,13-diHOME as compared to vehicle treatment by Student’s t-test.