Figure 2. Obesity in MC4RF51L mice is associated with hyperphagia.

(A) Average daily food intake measured every 7 days for 5 weeks in male and female MC4RF51L and WT mice (n = 4–13/group). (B) Average daily energy expenditure (EE) calculated weekly for 5 weeks in male and female MC4RF51L and WT mice. (C) REE and TEE measured by indirect calorimetry and normalized to lean mass (LM) in 3-month-old male MC4RF51L and WT mice (n = 5–6/group). (D) Total and ambulatory (Amb) activity levels in male MC4RF51L and WT mice at 3 months of age (n = 5–6/group). (E) RERs (vCO₂/vO₂) at 22°C in 3-month-old male MC4RF51L and WT mice at 3 months of age (n = 5–6/group). (F) Cold tolerance test. Rectal temperature in 4-month-old male MC4RF51L and WT mice at room temperature (0 hours) or at the indicated time points after being placed in an environment with a 6°C ambient temperature (n = 6–9/group). Meal frequency (G) and meal size (H) measured in 3 month-old male mice during daylight and nighttime hours at 22°C and 30°C (n = 5–6/group). Meal size was significantly increased in MC4RF51L mice compared with WT mice as determined by 2-way ANOVA. Data represent mean ± SEM. *P < 0.05, **P < 0.01 vs. WT by unpaired t test.