FIG. 6.

SIRT3-deficient mice show normal adaptive thermogenesis. (A) SIRT3-deficient mice show wild-type levels of UCP-1. UCP-1 protein levels were assessed in BAT mitochondrial extracts from wild-type (WT) and SIRT3 knockout (KO) animals from three different litters. Levels of Hsp60 and MnSOD were measured as loading controls. (B) Normal BAT morphology in SIRT3 KO mice. Hematoxylin-eosin staining is shown. Original magnification, ×400. (C) Normal adaptive thermogenesis in SIRT3 KO mice. (Left) SIRT3 KO and WT cohorts are similar in both pre- and post-cold exposure body weights. (Middle) SIRT3 KO and WT mice lose equal percentages of body weight during 6 h of cold exposure (4°C). ns, not significant. (Right) Core body temperatures of 7- to 10-week-old male SIRT3 KO and WT mice during exposure to 4°C for 6 h. Data represent the means ± SEM for three animals per genotype.