Nam S Y, Lee E J, Kim K R, Cha B S, Song Y D, Lim S K, Lee H C, Huh K B
Department of Internal Medicine, Yong Dong Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea.
Int J Obes Relat Metab Disord. 1997 May;21(5):355-9. doi: 10.1038/sj.ijo.0800412.
We investigated the effect of obesity on the serum levels of total and free IGF-1 and their relationship to the circulating levels of insulin and IGF binding proteins (IGFBPs) in age and sex-matched groups.
The study included 43 obese subjects (ideal body weight; IBW > 120%) and 45 controls (IBW < 100%). All of the subjects were male.
Total IGF-1, free IGF-1, IGFBP-1, IGFBP-2, IGFBP-3, and insulin were measured in obese subjects and normal control subjects.
No significant differences in the circulating levels of total and IGFBP-3 were observed between the obese and control groups. In contrast to total IGF-1, free IGF-1 in obese subjects was significantly increased compared to normal controls (P < 0.05). Serum total and free IGF-1 were inversely correlated with age (r = -0.42, P = 0.001, and -0.44, P = 0.001). Fasting serum insulin concentrations were elevated in all the obese subjects (P < 0.05) and positively correlated with IBW (r = 0.57, P = 0.001). The levels of serum GH and IGFBP-1 were suppressed in all the obese subjects (P < 0.05). IGFBP-1 was inversely correlated with IBW (r = -0.51, P = 0.001) and serum insulin concentrations (r = -0.48, P = 0.001). The IGFBP-2 concentrations were also suppressed in obese subjects and inversely related to free IGF-1 (r = -0.48, P = 0.001). Using multiple linear regression analysis, total IGF-1 and insulin concentrations were positively correlated (r = 0.58, P = 0.001) and free IGF-1 and IGFBP-1 concentrations were negatively correlated (r = -0.57, P = 0.001).
We confirmed that total IGF-1 and IGFBP-3 concentrations were not significantly different between the obese and control groups, despite GH hyposecretion in obesity. We also found that free IGF-1 concentrations were higher in obese subjects than in normal controls. It seems likely that overnutrition and chronic hyperinsulinaemia in obesity may alter this regulated growth response by insulin stimulation of IGF-1 production and suppression of hepatic IGFBP-1 and IGFBP-2 production, which may inhibit IGF-1 bioactivity.
我们在年龄和性别匹配的组中研究了肥胖对血清总胰岛素样生长因子-1（IGF-1）和游离IGF-1水平的影响，以及它们与胰岛素和IGF结合蛋白（IGFBPs）循环水平的关系。
该研究纳入了43名肥胖受试者（理想体重；IBW>120%）和45名对照者（IBW<100%）。所有受试者均为男性。
测定了肥胖受试者和正常对照者的总IGF-1、游离IGF-1、IGFBP-1、IGFBP-2、IGFBP-3和胰岛素。
肥胖组和对照组之间总IGF-1和IGFBP-3的循环水平未观察到显著差异。与总IGF-1相反，肥胖受试者的游离IGF-1与正常对照组相比显著升高（P<0.05）。血清总IGF-1和游离IGF-1与年龄呈负相关（r=-0.42，P=0.001，以及r=-0.44，P=0.001）。所有肥胖受试者的空腹血清胰岛素浓度均升高（P<0.05），且与IBW呈正相关（r=0.57，P=0.001）。所有肥胖受试者的血清生长激素（GH）和IGFBP-1水平均受到抑制（P<0.05）。IGFBP-1与IBW呈负相关（r=-0.51，P=0.001）以及与血清胰岛素浓度呈负相关（r=-0.48，P=0.001）。肥胖受试者的IGFBP-2浓度也受到抑制，且与游离IGF-1呈负相关（r=-0.48，P=0.001）。使用多元线性回归分析，总IGF-1和胰岛素浓度呈正相关（r=0.58, P=0.001），游离IGF-1和IGFBP-1浓度呈负相关（r=-0.57, P=0.001）。
我们证实，尽管肥胖存在GH分泌不足，但肥胖组和对照组之间总IGF-1和IGFBP-3浓度无显著差异。我们还发现肥胖受试者的游离IGF-1浓度高于正常对照组。肥胖中的营养过剩和慢性高胰岛素血症可能通过胰岛素刺激IGF-1产生以及抑制肝脏IGFBP-1和IGFBP-2产生来改变这种调节性生长反应，这可能会抑制IGF-1的生物活性。
