4周有氧运动与饮食控制对肥胖女青少年血清IGF-1和IGF-1结合蛋白-3水平的影响

目的：研究4周中等强度有氧运动结合饮食控制对肥胖女青年、少年血清总胰岛素样生长因子1（IGF-1）、IGF-1结合蛋白3（IGFBP-3）水平和IGF-1活性的影响及其在体脂减少和糖脂代谢改善中的作用。方法：招募9名18~19岁肥胖女青年和30名14~16岁肥胖女少年，进行全封闭的4周中等强度有氧运动结合饮食控制干预。运动项目有游泳、跑步、健身操等，每周运动6 d，每天运动4 h，每运动30 min，休息5 min。运动强度从第1周的低强度（运动后即刻心率约100~120次/分）递增至第2~4周的中强度（运动后即刻心率约120~140次/分）。根据基础代谢率给予每日1 400或1 600 kcal的总能量。另招募正常体重女青年和女少年各9名作为对照组。检测肥胖女青年、少年在4周干预前、后和对照组女青年、少年的体重、身体质量指数（BMI）、腰围、空腹血糖、胰岛素和血脂水平以及血清总IGF-1和IGFBP-3的水平和IGF-1活性。结果：①与对照组相比，肥胖女青年、少年的血清总IGF-1和IGFBP-3水平均降低且肥胖女少年的IGF-1活性降低；②4周中等强度有氧运动结合饮食控制在显著降低肥胖女青年、少年的体脂、腰围和改善糖脂代谢的同时，降低血清IGFBP-3水平、增加IGF-1活性，但血清总IGF-1水平没有显著改变。且相关性分析显示IGF-1活性增加可能与肥胖女青年的腰围减少有关，但血清IGFBP-3水平的降低和IGF-1活性的增加与糖脂代谢的改善没有显著相关性。结论：4周中等强度有氧运动结合饮食控制降低肥胖女青年、少年的血清IGFBP-3水平、增加IGF-1活性；且IGF-1活性的增加可能与运动结合饮食控制降低肥胖女青年的腰围有关。

Effects of aerobic exercise plus diet control on serum levels of total IGF-1 and IGF-1 binding protein-3 in female obese youths and adolescents

Objective: To investigate the effects of 4-week moderate aerobic exercise plus diet control on serum levels of total insulin-like growth factor 1(IGF-1) and IGF-1 binding protein-3 (IGFBP-3) as well as IGF-1 activity (reflected by molar ratio of IGF-1/IGFBP-3) in female obese adolescents and youths, and their possible role on fat loss, and improvement of glucose and lipid metabolism.Methods: Nine female obese youths (age:18~19 y) and 30 female obese adolescents (age:14~16 y) were recruited and undertook 4-week aerobic exercise such as swimming and jogging (6 days/week, twice a day, 2 h/time with 5 min rest per 30 min exercise) with gradual increase of intensity from low (heart rate immediately post-exercise of 1st week:100~120 beats/min) to moderate (heart rate immediately post-exercise of 2^nd-4^th weeks:120~140 beats/min) level, combined with a diet intervention (total daily energy intake of 1 400 or 1 600 kcal according to basal metabolism rate) in Shanghai Dianfeng weight loss enclosed camp. Nine normal weight young women and 9 female children matched at age and nationality were recruited as the normal control. Before and after the experimental period, anthropometric index (body weight, body mass index(BMI) and waist circumference), glucose and lipid metabolism parameters including fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), triglyceride (TG); total cholesterol (TC), low density lipoprotein (LDL) and high density lipoprotein (HDL), and serum levels of total IGF-1 and IGFBP-3 were measured, and IGF-1 activity was calculated in the obese and normal control female adolescents.Results: ①Compared with normal control, the serum levels of total IGF-1 and IGFBP-3 were decreased in the female obese youths and adolescents, and IGF-1 activity was reduced only in the obese female adolescents. ②The serum level of IGFBP-3 was down-regulated and IGF-1 activity was up-regulated while no change of serum total IGF-1 was induced by 4-week moderate aerobic exercise plus diet control, accompanied with significant decreases of body weight, BMI and waist circumference as well as improvement of glucose and lipid metabolism in the female obese youths and adolescents. Except for a positive association between the increased IGF-1 activity and the decreased waist circumference was found in the female obese youths by Pearson's correlation analysis, there was no relation of the decreased IGFBP-3, the increased IGF-1 activity with the improvements of anthropometric index and glucose and lipid metabolism in female obese youths and adolescents.Conclusion: The serum level of IGFBP-3 was down-regulated and the IGF-1 activity was up-regulated by 4-week moderate aerobic exercise plus diet control in female obese youths and adolescents. The increase of IGF-1 activity might be associated with the exercise-plus-diet-induced decrease of waist circumstance in female obese youths.