Effect of isocaloric diets and sibutramine on food intake, body mass variation and serum TNF-alpha levels in rats.

BACKGROUND/AIM: The effect of isocaloric diets and sibutramine on dietary behaviour and TNF-alpha is poorly understood. The aim of the study was to investigate the effects of isocaloric diets and sibutramine on food intake, body mass variation and serum TNF-alpha in free-feeding rats.

METHODS

Three groups of male Wistar rats (n = 63) were fed a high-fat diet, high-carbohydrate diet or high-protein diet for 13 weeks. In the last 3 weeks, each group was divided into 3 subgroups. Each subgroup received sibutramine 5 mg/kg, sibutramine 10 mg/kg or vehicle. Food intake was measured daily during the last week of the experiment; serum TNF-alpha was assayed and the body weight increasing rate was calculated.

RESULTS

The high-fat diet was associated with increased food intake, a greater weight gain ratio and increased TNF-alpha levels. Sibutramine treatment did not affect the dietary behaviour of high-protein- or high-carbohydrate-fed rats, while it significantly attenuated the daily food intake and body weight gain rate in the high-fat group, at the dose of 10 mg/kg. TNF-alpha levels were not affected by sibutramine.

CONCLUSIONS

High-fat feeding was associated with an increase in daily food intake, TNF-alpha levels and body weight gain rate, as well as with enhanced responsiveness to the anorectic effects of sibutramine. However, sibutramine did not affect TNF-alpha.