Figure 1. Female Dgat1−/− mice have increased energy expenditure and are protected from changes in body composition associated with age. (A) Normal food intake and (B) increased oxygen consumption in middle-aged Dgat1−/− mice (n = 11-12/genotype). (C) Reduced body weight and (D) fat mass in Dgat1−/− mice. Body weight was measured monthly in mice from the aging cohort (n = 30/genotype). Total body mass is expressed as fat and lean mass composition for young and middle-aged groups (n = 11-12/genotype). “Young” and “Middle-aged” refer to ages 3-4 months (mo) and 12-13 mo, respectively (*p < 0.05 vs. WT. #p <0.05 vs. same genotype, different age). (E) Reduced levels of triglycerides in heart and gastrocnemius from middle-aged (15 mo) female mice [*p < 0.05 vs. wild-type (WT); n = 8-13]. The inguinal fat pads from Dgat1−/− mice have fewer F4/80-positive (F) total leukocytes and (G) macrophages. (*p < 0.05 vs. WT; n = 5). F4/80-positive cells were separated into two populations, dim and bright, predicted to be the recruited and the resident macrophages, respectively [