Effects of risperidone on energy balance in female C57BL/6J mice

OBJECTIVE: To investigate the effect of risperidone on energy expenditure and weight gain in female C57BL/6J mice. DESIGN AND METHODS: Body weight and composition, food intake, energy expenditure, and activity were determined weekly. mRNA expression of uncoupling protein 1 in brown adipose tissue, orexin and brain-derived neurotrophic factor in the hypothalamus were quantified by Real-Time PCR. RESULTS: Risperidone tended to induce a greater body weight gain (P=0.052) and significantly higher food intake (P=0.038) relative to the placebo-treated group. Risperidone-treated mice had a higher resting energy expenditure (P=0.001), and total energy expenditure (P=0.005) than the placebo group. There were no effects of treatment, time, and treatment by time on NREE between groups. Risperidone-treated mice showed a significantly lesser locomotor activity than placebo-treated mice over 3 weeks (P<0.001). Risperidone induced a higher UCP1 mRNA (P=0.003) and a lower orexin mRNA (P=0.001) than placebo. DISCUSSION: Risperidone-induced weight gain is associated with hyperphagia and a reduction in locomotor activity in C57BL/6J mice. Additionally, higher total and resting energy expenditure were accompanied by higher levels of UCP1 mRNA in BAT. The increased total energy expenditure could not offset the total intake of energy through risperidone-induced hyperphagia, therefore resulting in weight gain in female C57BL/6J mice.