Hong Jina, Stubbins Renee E, Smith Rebekah R, Harvey Alison E, Núñez Nomelí P
Department of Nutritional Sciences, University of Texas at Austin, Austin, TX, USA.
Nutr J. 2009 Feb 17;8:11. doi: 10.1186/1475-2891-8-11.
The prevalence of obesity has increased dramatically. A direct comparison in the predisposition to obesity between males, premenopausal females, and postmenopausal females with various caloric intakes has not been made. To determine the effects of sex and ovarian hormones on the susceptibility to obesity, we conducted laboratory studies with mice. To eliminate confounders that can alter body weight gain, such as age and food consumption; we used mice with the same age and controlled the amount of calories they consumed.
We determined sex-specific susceptibility to obesity between male, non-ovariectomized female, and ovariectomized female mice. To compare susceptibility to gaining body weight between males and females, animals from each sex were exposed to either a 30% calorie-restricted, low-fat (5% fat), or high-fat (35% fat) diet regimen. To establish the role of ovarian hormones in weight gain, the ovaries were surgically removed from additional female mice, and then were exposed to the diets described above. Percent body fat and percent lean mass in the mice were determined by dual energy x-ray absorptiometry (DEXA).
In all three diet categories, male mice had a greater propensity of gaining body weight than female mice. However, ovariectomy eliminated the protection of female mice to gaining weight; in fact, ovariectomized female mice mimicked male mice in their susceptibility to weight gain. In summary, results show that male mice are more likely to become obese than female mice and that the protection against obesity in female mice is eliminated by ovariectomy.
Understanding metabolic differences between males and females may allow the discovery of better preventive and treatment strategies for diseases associated with body weight such as cancer and cardiovascular disease.
肥胖的患病率急剧上升。尚未对不同热量摄入情况下男性、绝经前女性和绝经后女性的肥胖易感性进行直接比较。为了确定性别和卵巢激素对肥胖易感性的影响，我们用小鼠进行了实验室研究。为了消除可能改变体重增加的混杂因素，如年龄和食物摄入量；我们使用了相同年龄的小鼠，并控制它们摄入的热量。
我们确定了雄性、未切除卵巢的雌性和切除卵巢的雌性小鼠对肥胖的性别特异性易感性。为了比较雄性和雌性之间体重增加的易感性，将每种性别的动物暴露于30%热量限制、低脂（5%脂肪）或高脂（35%脂肪）饮食方案中。为了确定卵巢激素在体重增加中的作用，对另外的雌性小鼠进行手术切除卵巢，然后让它们接触上述饮食。通过双能X线吸收法（DEXA）测定小鼠体内的体脂百分比和瘦体重百分比。
在所有三种饮食类别中，雄性小鼠比雌性小鼠有更大的体重增加倾向。然而，卵巢切除术消除了雌性小鼠对体重增加的保护作用；事实上，切除卵巢的雌性小鼠在体重增加易感性方面与雄性小鼠相似。总之，结果表明雄性小鼠比雌性小鼠更易肥胖，并且卵巢切除术消除了雌性小鼠对肥胖的保护作用。
了解雄性和雌性之间的代谢差异可能有助于发现针对与体重相关疾病（如癌症和心血管疾病）的更好的预防和治疗策略。
