Relationship between the expression of phosphatidylinositol 3-kinase and insulin resistance in women with gestational diabetes mellitus

Abstract

Objective To investigate the relationship between the expression of phosphatidylinositol 3-kinase(PI-3K)in skeletal muscles and insulin resistance in women with gestational diabetes mellitus(GDM). Methods The expression of PI-3K regulative subunit P85?mRNA and protein in skeletal muscle were determined by RT-PCR and Western blot in pregnant women with GDM(GDM group,n=030),normal pregnant women(normal group,n=30)and nonpregnant healthy women (control group,n=20).Fasting plasma glucose(FPG)and fasting insulin(FINS)were measured by oxidized assay and immunoradioassay.Insulin resistant index(HOMA-IR)was calculated. Results The levels of FPG,FINS,and HOMA-IR in GDM group [(5.61±0.78)mmol/L,(15.12±5.31)mU/L,and 1.21±0.52]were significantly higher than those of normal group[(4.43±0.46)mmol/L,(10.56±3.07)mU/L and 0.80±0.31;P<0.01].The expression of P85a mRNA (1.08±0.23)and protein(0.81±0.32)in GDM group were significantly higher than those in normal group(0.88±0.29 and 0.55±0.27,P<0.01)and control group(0.63±0.26 and 0.28±0.20,P<0.01).Expression of P85?mRNA and protein was positively correlated with HOMA-IR(r=0.625 and 0.759,P<0.01)in GDM group,but not in the control group. Conclusions Upregulated P85?mRNA and high expression of P85a protein in skeletal muscle may be one of the molecular mechanisms leading to insulin resisitance in GDM women. Key words: Diabetes,gestational; 1-Phosphatidylinosit01 3-kinase; Insulin resistance; Muscle,skeletal