Consumption of carbohydrate solutions enhances energy intake without increased body weight and impaired insulin action in rat skeletal muscles.

ABSTRACT

OBJECTIVES: In the present study, we investigated whether replacement of tap water by fructose or sucrose solutions affect rat body weight and insulin action in skeletal muscles. METHODS: Rats were fed standard rodent chow ad libitum with water, or water containing fructose (10.5% or 35%) or sucrose (10.5% or 35%) for 11 weeks. Body weight and energy intake from chow and drinking solutions were measured. Urinary catecholamines secretion was determined after 50-60 days. At the end of the feeding period, soleus and epitrochlearis were removed for in vitro measurements of glucose uptake (with tracer amount of 2-[3H]-deoxy-D-glucose) and PKB Ser473 phosphorylation (assessed by Western Blot) with or without insulin. RESULTS: Fructose and sucrose solutions enhanced daily energy intake by about 15% without increasing rat body weight. Secretion of urinary noradrenaline was higher in rats drinking a 35% sucrose solution than in rats drinking water. In the other groups, urinary noradrenaline secretion was similar to rats consuming water. Urinary adrenaline secretion was similar in all groups. Insulin-stimulated glucose uptake and insulin-stimulated PKB phosphorylation were not reduced by intake of fructose or sucrose solution. CONCLUSIONS: Fructose and sucrose solutions enhanced energy intake but did not increase body weight. Although noradrenaline may regulate body weight in rats drinking 35% sucrose solution, body weight seems to be regulated by other mechanisms. Intake of fructose or sucrose solution did not impair insulin-stimulated glucose uptake or signaling in skeletal muscles.