Seimon Radhika V, Hostland Nikita, Silveira Stephanie L, Gibson Alice A, Sainsbury Amanda
The Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia.
Horm Mol Biol Clin Investig. 2013 Sep;15(2):71-80. doi: 10.1515/hmbci-2013-0038.
Obesity treatments aim to maximize fat loss, particularly abdominal or visceral fat, without compromising lean or bone mass. However, the literature contains numerous examples of obesity treatments that - in addition to fat loss - result in loss of lean mass and/or bone mass.
Because of the known effects of energy restriction to increase activity of the hypothalamo-pitutiary adrenal (HPA) axis in lean humans and animals, and because increases in circulating glucocorticoid levels could potentially contribute to adverse body compositional changes with obesity treatments, we conducted a systematic PubMed search to determine whether HPA axis activation also occurs in response to energy restriction in obese humans and animals.
In most studies in obese humans, short-term severe energy restriction increased circulating cortisol levels, and this response was also seen in two longer-term human studies involving severe or moderate energy restriction. These findings parallel studies on short- or long-term energy restriction in obese rodents, with most studies showing increases in circulating corticosterone concentrations, and no change or actual increases in hypothalamic expression of corticotropin-releasing hormone, urocortin 3 or their receptors. However, a significant proportion of studies involving longer-term severe or moderate energy restriction in obese humans showed no change or decreases in HPA axis function. There was variability among human studies in the duration of energy restriction and timing of the HPA axis investigations (i.e., during energy restriction, or after a period of post-restriction weight maintenance). In order to unambiguously determine changes in HPA axis function with energy restriction in obese humans, it will be important to assess HPA axis function at multiple time points during energy restriction, given that obese individuals may spend many weeks or months in severe or moderate energy restriction in order to reduce excess weight, and given that increases in glucocorticoid function can have significant effects on body composition within weeks to months.
肥胖治疗旨在在不影响瘦体重或骨量的情况下，最大程度地减少脂肪，尤其是腹部或内脏脂肪。然而，文献中有许多肥胖治疗的例子，这些治疗除了减少脂肪外，还会导致瘦体重和/或骨量的减少。
由于已知能量限制会增加瘦的人类和动物下丘脑 - 垂体 - 肾上腺（HPA）轴的活性，并且由于循环糖皮质激素水平的升高可能会导致肥胖治疗引起不良的身体成分变化，我们进行了一项系统的PubMed搜索，以确定肥胖的人类和动物在能量限制时是否也会出现HPA轴激活。
在大多数针对肥胖人类的研究中，短期严重能量限制会增加循环皮质醇水平，在两项涉及严重或中度能量限制的长期人类研究中也观察到了这种反应。这些发现与肥胖啮齿动物短期或长期能量限制的研究相似，大多数研究表明循环皮质酮浓度增加，促肾上腺皮质激素释放激素、尿皮质素3或其受体在下丘脑的表达没有变化或实际增加。然而，相当一部分涉及肥胖人类长期严重或中度能量限制的研究表明HPA轴功能没有变化或下降。人类研究在能量限制的持续时间和HPA轴调查的时间（即能量限制期间或限制后体重维持一段时间后）方面存在差异。为了明确确定肥胖人类能量限制时HPA轴功能的变化，在能量限制期间的多个时间点评估HPA轴功能很重要，因为肥胖个体可能会花费数周或数月进行严重或中度能量限制以减轻超重，并且糖皮质激素功能的增加在数周数月内就会对身体成分产生显著影响。
