The gravitostat is a novel homeostatic body weight-regulating mechanism, mostly studied in mice, and recently confirmed in obese humans. In the present study, we explored the effect of weight loading on metabolic outcomes, meal patterns and parameters linked to energy expenditure in both obese and lean rats. Diet-induced obese (DIO) and lean rats were implanted with capsules weighing either 15% of biological body weight (load) or empty capsules (1.3% of body weight; controls). Loading protected against fat accumulation more markedly in the DIO group. In line with this, the obesity-related impairment in insulin sensitivity was notably ameliorated in DIO rats upon loading, as revealed by the reduction in serum insulin levels and homeostatic model assessment for insulin resistance index scores. Although 24-hour caloric intake was reduced in both groups, this effect was greater in loaded DIO rats than in loaded lean peers. During days 10-16, after recovery from surgery, loading: (i) decreased meal size in both groups (only during the light phase in DIO rats) but this was compensated in lean rats by an increase in meal frequency; (ii) reduced dark phase locomotor activity only in lean rats; and (iii) reduced mean caloric efficiency in DIO rats. Muscle weight was unaffected by loading in either group. Dietary-obese rats are therefore more responsive than lean rats to loading.

中文翻译：

---

Gravitostat 保护饮食诱导的肥胖大鼠免受脂肪堆积和体重增加

Gravitostat 是一种新的稳态体重调节机制，主要在小鼠中进行研究，最近在肥胖人类中得到证实。在本研究中，我们探讨了体重负荷对肥胖和瘦大鼠的代谢结果、膳食模式和与能量消耗相关的参数的影响。饮食诱导的肥胖 (DIO) 和瘦大鼠被植入重量为生物体重 (负载) 15% 的胶囊或空胶囊 (体重的 1.3%；对照)。在 DIO 组中，负荷能更明显地防止脂肪堆积。与此一致，肥胖相关的胰岛素敏感性损伤在 DIO 大鼠中显着改善，正如血清胰岛素水平的降低和对胰岛素抵抗指数评分的稳态模型评估所揭示的那样。尽管两组的 24 小时热量摄入都减少了，但这种影响在负荷 DIO 大鼠中比负荷较瘦的同龄人更大。在手术恢复后的第 10-16 天，负荷：(ii) 仅在瘦大鼠中降低暗期运动活动；(iii) DIO 大鼠的平均热量效率降低。肌肉重量不受任何一组负荷的影响。因此，饮食肥胖的大鼠比瘦大鼠对负荷的反应更灵敏。(i) 两组的进餐量减少（仅在 DIO 大鼠的光照阶段），但在瘦大鼠中，进餐频率的增加可以弥补这一点；(ii) 仅在瘦大鼠中降低暗期运动活动；(iii) DIO 大鼠的平均热量效率降低。肌肉重量不受任何一组负荷的影响。因此，饮食肥胖的大鼠比瘦大鼠对负荷的反应更灵敏。(i) 两组的进餐量减少（仅在 DIO 大鼠的光照阶段），但在瘦大鼠中，进餐频率的增加可以弥补这一点；(ii) 仅在瘦大鼠中降低暗期运动活动；(iii) DIO 大鼠的平均热量效率降低。肌肉重量不受任何一组负荷的影响。因此，饮食肥胖的大鼠比瘦大鼠对负荷的反应更灵敏。