Jørgensen J O, Vahl N, Dall R, Christiansen J S
Medical Department M (Endocrinology and Diabetes), Aarhus University Hospital, Denmark.
Metabolism. 1998 Sep;47(9):1134-9. doi: 10.1016/s0026-0495(98)90289-x.
Studies in patients with acromegaly and growth hormone (GH) deficiency, and administration of GH in normal and obese subjects and in patients with GH deficiency, suggest that GH increases resting metabolic rate (RMR) independently of changes in body composition. To test whether endogenous GH status determines RMR, we studied 38 healthy adults (18 women and 18 men) in two age groups (young, 30+/-0 years (n=18); older, 51+/-1 years [n=18]) with indirect calorimetry, deconvolution analysis of 24-hour GH secretion, arginin stimulation test, insulin-like growth factor-I (IGF-I) measurement, lean and fat tissue distribution (computed tomography [CT] and dual-energy x-ray absorptiometry), assessment of physical fitness (maximal oxygen consumption [VO2max]), thyroid status, and serum leptin levels. RMR was higher in men compared with women, whereas RMR per lean body mass (LBM) (kcal x 24 h(-1) x kg(-1)) was higher in women (30.0+/-0.5 v 33.0 2/3 0.8; P=.003). GH secretion was higher in women and in young people. Total-body fat (TBF) was higher in women, whereas LBM and abdominal fat were higher in men. Older people had significantly more TBF and abdominal fat as compared with younger people. VO2max was higher in younger people. Leptin levels were higher in women and in older people. Thyroid status was narrowly within the normal range in all subjects. RMR was strongly correlated with LBM (r=.90, P < .001). RMR/LBM correlated strongly with TBF (r=.49, P < .01) and leptin (r=.56, P < .001), but not with GH status. By multiple regression analysis, sex and TBF were the strongest predictors of RMR/LBM. However, in the young subgroup, GH production rate was a positive determinant of RMR/LBM. In the male subgroup, leptin was a stronger predictor than TBF of RMR/LBM (P < .001). Neither age, physical fitness, nor thyroid status contributed independently to predict RMR/LBM. In conclusion, (1) LBM was the most important determinant of RMR; (2) RMR/LBM was higher in women and depended strongly on TBF; (3) GH status in healthy adults was only weakly associated with RMR; and (4) in men, serum leptin levels were a strong positive determinant of RMR.
对肢端肥大症患者和生长激素（GH）缺乏患者的研究，以及在正常人和肥胖受试者以及生长激素缺乏患者中给予生长激素的研究表明，生长激素可独立于身体成分的变化而提高静息代谢率（RMR）。为了测试内源性生长激素状态是否决定静息代谢率，我们对38名健康成年人（18名女性和18名男性）进行了研究，分为两个年龄组（年轻人，30±0岁[n = 18]；老年人，51±1岁[n = 18]），采用间接测热法、24小时生长激素分泌的反卷积分析、精氨酸刺激试验、胰岛素样生长因子-I（IGF-I）测量、瘦组织和脂肪组织分布（计算机断层扫描[CT]和双能X线吸收法）、体能评估（最大耗氧量[VO2max]）、甲状腺状态和血清瘦素水平。男性的静息代谢率高于女性，而女性每瘦体重（LBM）的静息代谢率（千卡×24小时-1×千克-1）更高（30.0±0.5对33.0 2/3 0.8；P = 0.003）。女性和年轻人的生长激素分泌较高。女性的全身脂肪（TBF）较高，而男性的瘦体重和腹部脂肪较高。与年轻人相比，老年人的全身脂肪和腹部脂肪明显更多。年轻人的最大耗氧量更高。女性和老年人的瘦素水平更高。所有受试者的甲状腺状态均略在正常范围内。静息代谢率与瘦体重密切相关（r = 0.90，P < 0.001）。静息代谢率/瘦体重与全身脂肪（r = 0.49，P < 0.01）和瘦素（r = 0.56，P < 0.001）密切相关，但与生长激素状态无关。通过多元回归分析，性别和全身脂肪是静息代谢率/瘦体重的最强预测因素。然而，在年轻亚组中，生长激素产生率是静息代谢率/瘦体重的正向决定因素。在男性亚组中，瘦素比全身脂肪是静息代谢率/瘦体重更强的预测因素（P < 0.001）。年龄、体能和甲状腺状态均未独立对静息代谢率/瘦体重的预测产生影响。总之，（1）瘦体重是静息代谢率最重要的决定因素；（2）女性的静息代谢率/瘦体重更高，且强烈依赖于全身脂肪；（3）健康成年人的生长激素状态与静息代谢率仅存在微弱关联；（4）在男性中，血清瘦素水平是静息代谢率的强正向决定因素。
