蛋白激酶B对3T3-L1脂肪细胞脂联素蛋白质表达的调控

Akt regulating adiponectin secretion in 3T3-L1 adipocytes

目的研究异丙肾上腺素及胰岛素对脂肪细胞脂联素蛋白表达的影响,探讨蛋白激酶B(Akt)对脂联素的调控作用。方法通过免疫印迹法检测胰岛素和异丙肾上腺素处理后的3T3-L1脂肪细胞脂联素蛋白的表达,并比较表达myrAkt后3T3-L1脂肪细胞脂联素的变化。结果异丙肾上腺素可明显降低3T3-L1脂肪细胞脂联素的蛋白质表达,胰岛素可纠正这一变化;表达myrAkt的3T3-L1脂肪细胞中脂联素明显减少,异丙肾上腺素可增加脂联素蛋白的表达,胰岛素不能纠正这一变化。结论3T3-L1脂肪细胞中,胰岛素可纠正异丙肾上腺素引起的脂联素的降低,Akt的活性增加抑制了3T3-L1脂肪细胞脂联素蛋白的表达,Akt参与了胰岛素对脂肪细胞内脂联素蛋白质表达的调节,但不是唯一的途径。

Objective To investigate the effects of isoproterenol and insulin on adiponectin secretion in 3T3-L1 adipocytes and to clarify whether protein kinase B （Akt） regulate adiponectin secretion. Methods The constitutively active Akt（myrAkt） was introduced into 3T3-L1 adipocytes with the use of adenovi- rus vectors and the cells were treated with insulin and isoproterenol. The secretion （ protein level） of adi- ponectin in the medium was determined by Western blot analysis. Results In 3T3-L1 adipocytes, isopro- terenol at the concentration of 10 μmol/L reduced the adiponectin secretion and insulin at the concentration of 5 nmol/L could block the inhibitory effect of isoproterenol. In 3T3-L1 adipocytes expressed myrAkt,adiponectin secretion decreased significantly, isoproterenol treatment increased adiponectin and insulin couldn＇t block the effect of isoproterenol. Conclusion In 3T3-L1 adipocytes,insulin can block the inhibitory effect of isoproterenol on adiponectin secretion. Activation of Akt kinase can inhibit adiponectin secretion. Akt plays a role in some,but not all,in the effect of insulin on adiponectin secretion.