Hepatic and whole-body fat synthesis in humans during carbohydrate overfeeding
Hepatic and whole-body fat synthesis in humans during carbohydrate overfeeding
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DOI：
10.1093/ajcn/65.6.1774
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发表时间：
1997-06-01
影响因子：
7.1
通讯作者：
Wolfe, RR
中科院分区：
文献类型：
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作者：
Aarsland, A;Chinkes, D;Wolfe, RR
在人体中将碳水化合物转化为脂肪的能力的大小仍然是有争议的，因为它在肝脏中发生的程度与脂肪组织相反。我们计算了全身净脂肪合成间接热量和底物平衡数据从5名健康男性在基础状态和1和4天后的高能碳水化合物饮食（约2.5倍的能量消耗）。同时，测量肝脏中合成的脂肪酸的分泌，以确定脂肪合成在脂肪生成状态下在肝脏中发生的程度。基础状态下的呼吸交换率（RER）为0.81 +/- 0.01，第1天和第4天分别为0.99 +/- 0.025和1.15 +/- 0.022。尽管在基础状态下存在净脂肪氧化（955 +/- 139 mg.kg（-1）.min（-1）），但在早期（第1天; 481 +/- 205 mg.kg（-1）.min（-1））和晚期（第4天; 2243 +/- 253 mg.kg（-1）.min（-1））碳水化合物过量喂养期间，在全身水平上存在净脂肪合成。尽管在研究期间，从头合成的脂肪的肝脏分泌增加了约35倍（基础状态，1.0 +/- 0.3;第1天，13.8 +/- 6.8;第4天，43.3 +/- 16.3 mg.kg（-1）.min（-1）），但这只能解释总脂肪合成的一小部分。我们的结论是，当多余的碳水化合物能量转化为脂肪时，肝脏在人体内起着定量的次要作用。脂肪合成的主要部位可能是脂肪组织。
The magnitude of the capacity to convert carbohydrate to fat in the human body is still controversial, as is the extent to which it takes place in the liver as opposed to the adipose tissue. We calculated whole-body net fat synthesis from indirect calorimetry and substrate balance data from five healthy men in the basal state and after 1 and 4 d on a hyperenergetic carbohydrate diet (approximate to 2.5 times energy expenditure). At the same time, the secretion of fatty acids synthesized in the liver was measured to determine the extent to which fat synthesis occurs in the liver in a lipogenic state. The respiratory exchange ratio (RER) was 0.81 +/- 0.01 in the basal state and 0.99 +/- 0.025 and 1.15 +/- 0.022 on days 1 and 4, respectively. Although there was net fat oxidation in the basal state (955 +/- 139 mg.kg(-1).min(-1)), there was net fat synthesis at the whole-body level both during early (day 1; 481 +/- 205 mg.kg(-1).min(-1)) and late (day 4; 2243 +/- 253 mg.kg(-1).min(-1)) carbohydrate overfeeding. Although hepatic secretion of fat synthesized de novo increased approximate to 35-fold during the study (basal state, 1.0 +/- 0.3; day 1, 13.8 +/- 6.8; and day 4, 43.3 +/- 16.3 mg.kg(-1).min(-1)) this could only account for a small portion of total fat synthesis. We conclude that the liver plays a quantitatively minor role when surplus carbohydrate energy is converted into fat in the human body. The main site for fat synthesis is likely to be the adipose tissue.