睾酮对胰岛素敏感细胞胰岛素受体底物1和葡萄糖转运载体4表达的影响

Effects of testosterone on insulin receptor substrate-1 and glucose transporter 4 expression in cells sensitive to insulin

目的探讨雄激素对胰岛素敏感性影响的可能的分子机制。方法诱导3T3-L1前脂肪细胞系和C2C12成肌细胞系分别分化为3T3-L1脂肪细胞和C2C12骨骼肌细胞，然后对这两种细胞分别以10^-9mol／L睾酮处理4、8、12、24及48h，并以不同浓度（10^-12～10^-5mol／L）的睾酮处理24h，用Western印迹的方法检测两种细胞在以两种方法处理后胰岛素受体底物1（IRS-1）和葡萄糖转运载体4（GLUT4）表达的变化。结果随着10^-9mol／L浓度的睾酮处理时间的延长，IRS-1和GLUT4在两种细胞的表达逐渐增加，IRS-1于12h达峰后下降。3T3-L1脂肪细胞及C2C12骨骼肌细胞中12h峰值分别是0h对照的（1．42±0．42）倍和（1．53±0．14）倍，均P〈0．05；GLUT4于24h达峰后表达下降[313-L1脂肪细胞及C2C12骨骼肌细胞中24h峰值分别是0h的（3．22±0．10）倍和（5．17±1．06）倍，均P〈0．05]。当睾酮处理浓度从10^-12mol／L逐渐增加时，IRS-1在两种细胞的表达逐渐增加，于10^-9mol／L达峰值后表达逐渐下降[在313-L1脂肪细胞和C2C12骨骼肌细胞，10^-9mol／L睾酮处理后的峰值较空白对照分别增加（4．23±0．27）倍和（3．16±0．15）倍，均P〈0．05]。GLUT4在C2C12骨骼肌细胞的表达随着睾酮浓度的升高有增加的趋势[经10^-7mol／L睾酮处理后的表达量是空白对照的（2．99±0．15）倍，P〈0．05，于10^-7mol／L后增加趋势不明显。在313．L1脂肪细胞中，GLUT4的表达于10^-11mol／L达峰值[较空白对照增加（2．58±0．02）倍，P〈0．05]，然后随着睾酮浓度的升高表达下降。结论睾酮影响胰岛素信号转导分子的表达存在剂量和时间上的双向作用。

Objective To investigate the molecular mechanism of the influence of testosterone （T） on insulin sensitivity. Methods Preadipocytes of the line 3T3-L1 and myoblasts of the line C2C12 were cultured to develop into mature adipocytes and skeleton muscle cells. Testosterone of the concentration of 10^-9 mol/1 was added into the culture fluids for 0, 4, 8, 12, 24 and 40 hours. And testosterone of the concentrations increased by 10 times from 10^-12 mol/L, 10^-5 mol/L was added for 24 hours. Then the cell protein was extracted and the expression of insulin receptor substrate-1 （ IRS-1 ） and glucose transporter 4 （GLUT4） in were measured by Western blotting. Result （ 1 ） Treated with T of the concentration of 10 ^-9 mol/L, the IRS-1 expression in the 3T3-L1 adipocytes increased along with the treatment time , peaked 12 hours later with a peak value 1.42 ± 0.42 times that at the 0 h, and the values 4, 8, and 24 hours later were 1.13 ±0.03, 1.19 ±0.05, and 1.08 ±0.02 times that at the 0 h （ all P 〈0.05）. The expression of IRS-1 in the C2C12 cells increased along with the treatment time of the testosterone of the concentration of 10-9 mol/L too, peaked 24 hours later, with the values 8, 12, and 24 hours later 1.41 ±0.18, 1.53 ±0. 14, and 1.50 ± 0. 14 times that at the 0 h （ all P 〈 0.05 ）. The GLUT4 expression value in the 3T3-L1 adipocytes increased since 4 hours after the treatment, peaked 24 hours after the treatment （3.22 ± 0. 10 that at the 0 h） （all P 〈0.05）. The GLUT4 expression value in the C2C12 cells increased since 4 hours after the treatment, peaked 24 hours after the treatment （5.17 ± 1.06 that at the 0 h） （ all P 〈0.05）. （2）The IRS-1 expression in the 3T3-L1 adipocytes and C2C12 cells increased dose-dependently along with the increase of the T concentration and peaked when the T concentration was 10^-9 mol/l （4.23 ±0.27 and 3.16 ± 0. 15 times that of blank controls respectively, both P 〈 0.05 ） , and then turned to decrease. （3） The GLUT4 expression in the C2C12 cells increased along with the increase of the T concentration, peaked when the T concentration was 10^-7moL/L （2.99 ±0. 15 times that of the blank control, P 〈0.05 ） , and then remained at the similar level. （4） The GLUT4 expression in the 3T3-L1 adipocytes was highest when treated with 10 ^11 moL/L testosterone （2.58 ± 0.02 times that of the blank control, P 〈 0.05 ）, and then decreased along with the increase of the T concentration （ P 〈 0.05 ）. Conclusion Testosterone has bidirectional dose- and time-dependent effects on the cellular expression of IRS-1 and GLUT4, which increase with low dose and short time testosterone treatment and decrease with higher dose and longer time treatment.