Effect of Prandial Glucose on Brown Fat Thermogenesis in Rats: Possible Implications for Dietary Obesity

We have previously shown that a single meal results in an increased thermic activity of brown adipose tissue (BAT). In the present study, we examine the importance of the availability of glucose in the test meal and in the incubation medium on the rate of in vitro respiration of BAT. We show that a high glucose test meal results in a significant increase in BAT weight and in its in vitro rate of respiration and that the effect of the high glucose meal on brown fat thermogenesis is significantly greater than that of an equicaloric high fructose meal. These data suggest that a decreased postprandial BAT thermogenesis may contribute to the increased metabolic efficiency and to the obesity reported to be associated with sucrose consumption in the rat. We also show that the reduced in vitro rate of respiration of BAT from meal-deprived rats is largely corrected by the addition of glucose and insulin to the incubation medium.