Abstract:

To investigate the role of insulin in the expression of  sodium channel β subunit (β-ENaC) in alveolar epithelial A549 cells,and

to clarify the possible signaling pathway on regulating β-ENaC by insulin. Methods The alveolar epithelial A549 cells were

cultured in vitro and  divided into control group,insulin group (A549 cells were incubated with 2,20， and 200 mU•L^-1 insulin  for 

30,60,and 120 min),and LY294002 group,respectively.The expression levels of mRNA and protein of  β-ENaC and  p-Akt protein were

determined by RT-PCR and Western blotting methods.Results Compared with control group，the expression levels of β-ENaC mRNA and

protein were elevated significantly after treated with 2,20,and  200 mU•L^-1 insulin in a concentration-dependent manner

(P<0.05).Compared with control group，the expression levels of p-AKt protein were elevated significantly after treated with 

2,20,and 200 mU?L-1 insulin(P<0.05)　in a concentration-dependent manner.Compared with control group，the expression levels of β-

ENaC mRNA and protein were elevated significantly after treated with insulin for 30,60,and  120 min in a time-dependent manner

(P<0.05).Compared with insulin group，the expression levels of β-ENaC mRNA and protein and  p-Akt protein in LY294002 group were

decreased(P<0.05).Conclusion Activation of PI3K/Akt signaling pathway can increase  the expression levels of β-ENaC mRNA and

protein,which is beneficial for clearance of pulmonary edema fluid.

Key words: epithelial sodium channel &beta, subunit;phosphatidylinositol 3-kinase;protein kinase B;signaling pathway；insulin