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目的 研究磷脂酰肌醇 3-激酶 (PI3K)信号通路对血管紧张素 (Ang )与胰岛素诱导的血管平滑肌细胞蛋白质合成的影响 ,及该信号系统对 4 E结合蛋白 1(4 E- BP1)和核糖体蛋白 S6激酶磷酸化的介导作用。 方法 体外培养 8周龄的 SD大鼠平滑肌细胞 ,(1) 3H亮氨酸掺入法测定蛋白合成 ;(2 ) Western印迹法检测蛋白激酶 B(PKB)、4 E- BP1和核糖体蛋白 S6激酶的磷酸化。 结果 (1)与对照组相比 ,Ang (10 0 nmol/ L )与胰岛素 (10 0 nm ol/ L )对血管平滑肌细胞的 3H亮氨酸掺入有显著刺激作用 [Ang (× 10 3cpm) :8.0 0± 0 .5 4 vs 5 .15± 0 .2 6 ,P<0 .0 5 ;胰岛素 :6 .13± 0 .31vs5 .0 5± 0 .35 ,P<0 .0 5 ]。 PI3K抑制剂 L Y2 94 0 0 2使 Ang 的 3H亮氨酸掺入刺激作用受到抑制 ,抑制率 :0 .1μmol/ LL Y2 94 0 0 2 :38% (P<0 .0 5 ) ;1μmol/ L L Y2 94 0 0 2 :6 2 % (P <0 .0 5 )。同样浓度的 L Y2 94 0 0 2对胰岛素的 3H亮氨酸掺入刺激作用的抑制率分别为 4 3% (P<0 .0 5 ) ,5 7% (P<0 .0 5 ) ,97% (P<0 .0 5 )。(2 )静止的血管平滑肌细胞中加入 Ang 或胰岛素 ,显著增加 PKB的磷酸化。Ang 刺激的 PKB磷酸化于 5 m in达高峰 ,胰岛素刺激的 PKB磷酸化于 30 m in达高峰。PKB抑制剂 L Y2 94 0 0 2以剂量
Objective To investigate the effects of phosphatidylinositol 3-kinase (PI3K) signaling pathway on angiotensin (Ang) and insulin-induced protein synthesis in vascular smooth muscle cells (VSMCs) and the effects of this signaling system on 4 E-binding protein 1 Ribosomal protein S6 kinase phosphorylation mediated. Methods 8-week-old SD rat smooth muscle cells were cultured in vitro. (1) The 3H-leucine incorporation method was used to determine the protein synthesis. (2) Protein kinase B (PKB), 4 E- BP1 and ribosomal protein S6 Kinase phosphorylation. Results (1) Compared with the control group, Ang (10 3 cpm) was significantly stimulated by 3H-leucine incorporation of vascular smooth muscle cells with Ang (100 nmol / L) and insulin (100 nmol / L) : 8.0 0 ± 0.54 vs 5 .15 ± 0.2 6, P <0.05; insulin: 6 .13 ± 0.31 vs5. 05 ± 0.35, P <0.05). PI3K inhibitor L Y2 94 0 0 2 inhibited the incorporation of 3H-leucine into Ang-3 cells. The inhibitory rates were: 0.1 μmol / L Y2 94 0 0 2: 38% (P <0.05); 1 μmol / LL Y2 94 0 0 2: 6 2% (P <0 .0 5). The inhibitory rates of LY2 94 0 0 2 with the same concentration on insulin 3H-leucine incorporation were 43% (P <0. 05), 57% (P <0. 05), 97 % (P <0 .0 5). (2) Addition of Ang or insulin to resting vascular smooth muscle cells significantly increased PKB phosphorylation. Ang-stimulated phosphorylation of PKB peaked at 5 min, and insulin-stimulated PKB phosphorylation peaked at 30 min. PKB inhibitor L Y2 94 0 0 2 at dose