Comparative effects of the antipsychotics sulpiride and risperidone in female rats on energy balance, body composition, fat morphology and macronutrient selection.

Previous studies showed that the antipsychotic drugs (APDs) sulpiride (SUL) and risperidone (RIS) induced body weight gain (BWG), hyperphagia, and increased serum levels of leptin, prolactin and corticosterone in female rats. Neither SUL nor RIS increased BWG or food intake (FI) in male rats. To further develop the animal model of APD-induced obesity, SUL (20 mg/kg/sc), RIS (0.5 mg/kg/sc) or vehicle (1 cm(3)/kg/sc) were administered to female Wistar rats for 10 or 12 days. Body composition, fat tissue morphology, energy expenditure and food efficiency were assessed in animals fed a high-fat diet. In another experiment, macronutrient selection was evaluated in animals fed with pure diets. SUL and RIS significantly increased BWG and FI, with a stronger effect of SUL. Both drugs increased fat gain and food efficiency, and did not modify energy expenditure. Obesity was due to adipocyte hyperplasia. SUL-treated rats significantly decreased fat intake (p = 0.039), showed a tendency to increase protein intake and did not modify carbohydrate consumption. No differences were observed between the RIS and the vehicle group. The macronutrient selection pattern differs from that observed in obese people undergoing APD treatment and in most animal models of obesity. Those findings suggest that SUL administration does not properly model APD treatment in humans. Results on macronutient selection in RIS-treated rats must be considered as preliminary, since in this experiment the animals did not gain weight significantly. Other diet protocols and lower APD doses must be tested to further characterize the RIS model.