Expression and tyrosine phosphorylation of insulin receptor substrate-1 in adipose tissue from patients with gestational diabetes mellitns / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the expression and tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and in the adipose tissue of patients with gestational diabetes mellitus (GDM), and to explore molecular mechanisms of insulin resistance in GDM. Methods The serum and adipose tissue were sampled from patients with GDM (GDM group, n = 20) and normal pregnant women (control group, n = 20). Fasting plasma glucose was measured by glucose oxidase assay. The expressions of IRS-1 protein and mRNA were determined by Western blot and semi-quantitative RT-PCR. The tyrosine phosphorylation of IRS-1 was measured by immunoprecipitation. Results Compared with control group, in GDM group, the expression of IRS-1 mRNA was markedly decreased (0.61 ±0.06 vs 1.12 ± 0.17, P < 0.01), the expression of IRS-1 protein was significantly decreased (0.57 ±0.08 vs O. 83 ±0.07, P <0.01) and tyrosine phosphorylation was significantly reduced (0.23 ± O. 06 vs O. 62 ±0.04, P < 0.01) in the adipose tissue. Conclusion The decline of protein expression and tyrosine phosphorylation of IRS-1 in the adipose tissue of gestational diabetes appears to be one of the moleculemechanisms of insulin resistance in patients with GDM.