Fig. 5.

Post-weaning energy intake (A), growth (B), adiposity (C), energy expenditure (D), and voluntary activity (E) of β₃-AR-null mice provided a control or methionine-restricted diet with or without propranolol. Twenty-four 10- to 12-wk-old male FVB mice with targeted deletion of the β₃-AR (27) were randomly assigned to four groups. Two of the groups received either a control diet containing 0.86% methionine (Control group) or the control diet formulated to contain 500 μg propranolol per gram of diet (Control + propranolol). The remaining two groups received either a diet with methionine restricted to 0.17% (MR) or the MR diet formulated to contain 500 μg propranolol per gram of diet (MR + propranolol). The diets were provided ad libitum for 12 wk. Energy intake (A), body weight (B), body composition (C) were measured at weekly intervals for 12 wk, as described in materials and methods. Thereafter, mice were adapted to calorimetry chambers for 24 h prior to measurement of O₂ consumption, CO₂ production, and voluntary activity for the following 4 days. Thereafter, fat pads were harvested. Average EE was calculated for each animal in each group for the period when lights were on (7 AM–7 PM), when lights were off (7 PM–7 AM), and averaged over both periods to assess total daily EE. Total activity was averaged for each animal in each group for the period when lights were on or off and also averaged over both periods to assess total activity. Response variables were analyzed by ANOVA. ^a,b,cMeans at each time point with letters that differ denote P < 0.05.