Valle A, Català-Niell A, Colom B, García-Palmer F J, Oliver J, Roca P
Grup de Metabolisme Energètic y Nutrició, Departament de Biologia Fonamental i Ciències de la Salut, Universitari d'Investigació en Cièncias de la Salut, Universitat de les Illes Balears. Cra. Valldemossa km 7.5. E-07122, Palma de Mallorca, Spain.
Am J Physiol Endocrinol Metab. 2005 Jul;289(1):E15-22. doi: 10.1152/ajpendo.00553.2004. Epub 2005 Feb 8.
Sex-related differences in energy balance were studied in young Wistar rats fed standard chow pellets either ad libitum or in restricted amounts (60% of ad libitum intake) for 100 days. Caloric intake, indirect calorimetry, organ and adipose tissue weights, energy efficiency, liver mitochondrial respiration rate, and brown adipose tissue (BAT) uncoupling protein-1 (UCP1) content were measured. Ad libitum-fed females showed greater oxygen consumption (Vo(2)) and carbon dioxide production (Vco(2)) and lower energy efficiency than males. Caloric restriction induced a chronic drop of Vo(2) and Vco(2) in females but not in males over the period studied. Restricted females showed a better conservation of metabolic active organ mass and a greater decrease in adipose depots than restricted males. Moreover, changes of BAT size and UCP1 content suggest that BAT may be the main cause responsible for sex differences in the response of energy balance to caloric restriction. In conclusion, our results indicate that females under caloric restriction conditions deactivate facultative thermogenesis to a greater degree than males. This ability may have obvious advantages for female survival and therefore the survival of the species when food is limiting.
对自由采食标准鼠粮颗粒或限制食量（自由采食量的60%）达100天的幼年Wistar大鼠的能量平衡性别差异进行了研究。测量了热量摄入、间接测热法、器官和脂肪组织重量、能量效率、肝脏线粒体呼吸率以及棕色脂肪组织（BAT）解偶联蛋白-1（UCP1）含量。自由采食的雌性大鼠比雄性大鼠表现出更高的耗氧量（Vo(2)）和二氧化碳产生量（Vco(2)）以及更低的能量效率。在研究期间，热量限制导致雌性大鼠的Vo(2)和Vco(2)持续下降，但雄性大鼠未出现这种情况。与限制食量的雄性大鼠相比，限制食量的雌性大鼠在代谢活跃器官质量的维持方面表现更好，脂肪储备减少得更多。此外，BAT大小和UCP1含量的变化表明，BAT可能是能量平衡对热量限制反应中性别差异的主要原因。总之，我们的结果表明，在热量限制条件下，雌性大鼠比雄性大鼠更能有效地抑制兼性产热。当食物有限时，这种能力可能对雌性大鼠的生存以及物种的生存具有明显优势。
