Section on Growth and Obesity, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1103, USA.
J Clin Endocrinol Metab. 2013 Apr;98(4):1676-84. doi: 10.1210/jc.2012-3817. Epub 2013 Feb 28.
In obesity, increases in free fatty acid (FFA) flux can predict development of insulin resistance. Adult women release more FFA relative to resting energy expenditure (REE) and have greater FFA clearance rates than men. In adolescents, it is unknown whether sex differences in FFA flux occur.
Our objective was to determine the associations of sex, REE, and body composition with FFA kinetics in obese adolescents.
Participants were from a convenience sample of 112 non-Hispanic white and black adolescents (31% male; age range, 12-18 years; body mass index SD score range, 1.6-3.1) studied before initiating obesity treatment.
Glucose, insulin, and FFA were measured during insulin-modified frequently sampled iv glucose tolerance tests. Minimal models for glucose and FFA calculated insulin sensitivity index (SI) and FFA kinetics, including maximum (l0 + l2) and insulin-suppressed (l2) lipolysis rates, clearance rate constant (cf), and insulin concentration for 50% lipolysis suppression (ED50). Relationships of FFA measures to sex, REE, fat mass (FM), lean body mass (LBM) and visceral adipose tissue (VAT) were examined.
In models accounting for age, race, pubertal status, height, FM, and LBM, we found sex, pubertal status, age, and REE independently contributed to the prediction of l2 and l0 + l2 (P < .05). Sex and REE independently predicted ED50 (P < .05). Sex, FM/VAT, and LBM were independent predictors of cf. Girls had greater l2, l0 + l2 and ED50 (P < .05, adjusted for REE) and greater cf (P < .05, adjusted for FM or VAT) than boys.
Independent of the effects of REE and FM, FFA kinetics differ significantly in obese adolescent girls and boys, suggesting greater FFA flux among girls.
在肥胖症中，游离脂肪酸（FFA）通量的增加可以预测胰岛素抵抗的发展。成年女性相对于静息能量消耗（REE）释放更多的 FFA，并且 FFA 清除率高于男性。在青少年中，尚不清楚是否存在 FFA 通量的性别差异。
本研究旨在确定性别、REE 和身体成分与肥胖青少年 FFA 动力学的相关性。
参与者来自一个方便取样的 112 名非西班牙裔白人和黑人青少年（31%为男性；年龄范围 12-18 岁；体重指数 SD 评分范围 1.6-3.1），在开始肥胖治疗前进行了研究。
在胰岛素改良的频繁采样静脉葡萄糖耐量试验期间测量血糖、胰岛素和 FFA。最小模型用于计算葡萄糖和 FFA 的胰岛素敏感性指数（SI）和 FFA 动力学，包括最大（l0 + l2）和胰岛素抑制（l2）脂肪分解率、清除率常数（cf）和 50%脂肪分解抑制的胰岛素浓度（ED50）。检查 FFA 指标与性别、REE、脂肪量（FM）、瘦体量（LBM）和内脏脂肪组织（VAT）的关系。
在考虑年龄、种族、青春期状态、身高、FM 和 LBM 的模型中，我们发现性别、青春期状态、年龄和 REE 独立地预测了 l2 和 l0 + l2（P <.05）。性别和 REE 独立预测 ED50（P <.05）。性别、FM/VAT 和 LBM 是 cf 的独立预测因子。与男孩相比，女孩的 l2、l0 + l2 和 ED50 更大（P <.05，调整 REE 后），cf 也更大（P <.05，调整 FM 或 VAT 后）。
独立于 REE 和 FM 的影响，肥胖青少年女孩和男孩的 FFA 动力学存在显著差异，表明女孩的 FFA 通量更大。
