ABSTRACT
The relationship between tyrosine phosphorylation (TP) and protein expression of insulin receptor (InsR) and insulin resistance (IR) in patients with gestational diabetes mellitus (GDM) was investigated. The InsR expression and TP in skeleton muscle tissue were determined by Western blotting and immunoprecipitation in women with GDM (GDM group, n=22), normal pregnant women (normal pregnancy group, n=22) and normal non-pregnant women (normal non-pregnant group, n=13). Fasting plasma glucose (FPG) and fasting insulin (FINS) were measured by oxidase assay and immunoradioassay. The results showed that the levels of FPG (5.61±0.78 mmol/L), FINS (15.42±5.13 mU/L) and Homeostasis model assessment-IR (HOMA-IR) (1.21±0.52) in GDM group were significantly higher than those in normal pregnancy group (4.43±0.46 mmol/L, 10.56±3.07 mU/L and 0.80±0.31 respectively) (P<0.01). The levels of FINS and HOMA-IR in normal pregnancy group were significantly higher than those in normal non-pregnant group (7.56±2.31 mU/L and 0.47±0.26 respectively) (P<0.01). There was no significant difference in the InsR expression level among the three groups (P>0.05). TP of InsR with insulin stimulation was significantly decreased in GDM group (0.20±0.05) as compared with normal pregnancy group (0.26±0.06) (P<0.01). TP of InsR with insulin stimulation in normal pregnancy group was lower than that in normal non-pregnant group (0.31±0.06) (P<0.01). TP of InsR with insulin stimulation was negatively related with HOMA-IR in GDM group (r=-0.525, P<0.01). There was no correlation between the protein expression of InsR and HOMA-IR in GDM group (r=-0.236, P>0.05). It was suggested that there is no significant correlation between the protein expression of InsR in skeletal muscle and IR in GDM, but changes in TP of InsR are associated with IR in GDM.
Subject(s)
Adult , Female , Humans , Pregnancy , Blood Glucose , Metabolism , Blotting, Western , Diabetes, Gestational , Blood , Metabolism , Fasting , Blood , Insulin , Blood , Insulin Resistance , Muscle, Skeletal , Metabolism , Phosphorylation , Radioimmunoassay , Receptor, Insulin , Metabolism , Tyrosine , MetabolismABSTRACT
The relationship between tyrosine phosphorylation (TP) and protein expression of insulin receptor (InsR) and insulin resistance (IR) in patients with gestational diabetes mellitus (GDM) was investigated. The InsR expression and TP in skeleton muscle tissue were determined by Western blotting and immunoprecipitation in women with GDM (GDM group, n=22), normal pregnant women (normal pregnancy group, n=22) and normal non-pregnant women (normal non-pregnant group, n=13). Fasting plasma glucose (FPG) and fasting insulin (FINS) were measured by oxidase assay and immunoradioassay. The results showed that the levels of FPG (5.61±0.78 mmol/L), FINS (15.42±5.13 mU/L) and Homeostasis model assessment-IR (HOMA-IR) (1.21±0.52) in GDM group were significantly higher than those in normal pregnancy group (4.43±0.46 mmol/L, 10.56±3.07 mU/L and 0.80±0.31 respectively) (P0.05). TP of InsR with insulin stimulation was significantly decreased in GDM group (0.20±0.05) as compared with normal pregnancy group (0.26±0.06) (P0.05). It was suggested that there is no significant correlation between the protein expression of InsR in skeletal muscle and IR in GDM, but changes in TP of InsR are associated with IR in GDM.
ABSTRACT
Objective To investigate the expression of phosphatidylinositol 3-kinase(PI-3K)in adipose tissue of polycystic ovary syndrome patients(PCOS),and explore molecular mechanisms of insulin resistance(IR)in PCOS.Methods Samples from patients with PCOS with IR(n=19),PCOS without IR (n=10)and controls(n=15)were collected.Serum fasting insulin(FIN)and fasting plasma glucose (FPG)were measure& Insulin resistance index was calculated using homeostasis model assessment (HOMA)to analyze the relationship between these markers and IR.Western blot technique was used to detect the PI-3K p85 subunit.Gene expression of PI-3K p85 subunit was detected by reverse transcription polymerase chain reaction(RT-PCR)method.Kinase activity was detected by immunoprecipitation,thin- layer chromatography and gamma scintillation counting.Results(1)The levels of FIN[(25.2?3.8) mU/L]and HOMA-IR(1.6?0.3)in PCOS with IR were significantly higher than those in PCOS without IR[(13.4 +3.8)mU/L,0.9?0.3]and controls[(9.5 +2.6)mU/L,0.5?0.3;all P＜0.05).(2) There was no significant difference in the protein(0.65?0.10)and gene expression(0.92?0.12)of PI-3 K p85 subunit in PCOS with IR compared with PCOS without IR(0.72?0.10,1.01?0.10)and control groups(0.73?0.14,1.00?0.12;P＞0.05).(3)PI-3K activity in PCOS with IR(81%)and PCOS without IR(89%)was significantly decreased(P＜0.01,P＜0.05)and negatively correlated with HOMA- IR(r=-0.69,P＜0.01;r=-0.62,P＜0.05).Conclusions No significant difference in the protein and gene expression of PI-3K p85 subunit in PCOS with IR is found.The decreased PI-3K activity may lead to IR of PCOS.