Metabolic rates were measured by indirect calorimetry in mice 4 weeks after treatment by using the Comprehensive Lab Animal Monitoring System (CLAMS, Columbus Instruments, USA). Mice were maintained at 24°C under a 12-h light/dark cycle. Food and water is available ad libitum. Mice were acclimatized to individual cages for 24 h before recording, and then underwent 24 h of monitoring. Each cage was monitored for metabolic parameters (including oxygen consumption and carbon dioxide production) at 25-min intervals throughout the 48 h period. Parameters of oxygen consumption (mL/h) and carbon dioxide production (mL/h) were recorded for each mouse. Heat production (energy expenditure) was calculated as described previously (Tseng et al., 2008).