Dietary obesity: brown fat denervation fails to alter development or recovery

We assessed the effect of scapular brown adipose tissue (BAT) denervation on dietary obesity in adult female Sprague-Dawley rats. In rats maintained for 32 days on an obesity-inducing regimen, BAT denervation produced significant reductions in food intake (83.4 vs. 94.4 kcal/day), weight gain (66.0 vs. 103.5 g), and carcass fat (19.3 vs. 27.6%). A subgroup of denervates consuming as many calories as controls (94.1 kcal/day) failed to gain more weight (92.2 g) or accumulate more fat (25.4%) than controls. In rats developing obesity for 32 days followed by 8 days on laboratory chow, weight change was unaffected by denervation during either weight gain (89.4 vs. 87.1 g for controls) or weight loss (21.2 vs. 22.1 g) phases, as was carcass fat (21.0 vs. 20.4%). BAT norepinephrine utilization was unchanged in nondenervated obese rats and those recovering from obesity. We did not, therefore, find evidence that under these experimental conditions sympathetic activation of BAT countered obesity during overconsumption or contributed to recovery from obesity.