GDM IRS-1酪氨酸磷酸化水平与其1223丝氨酸位点碱基突变的相关性

目的:探讨妊娠期糖尿病(GDM)患者脂肪组织中胰岛素受体底物1(IRS-1)蛋白质酪氨酸磷酸化程度,及与其1223丝氨酸位点碱基突变的相关性。方法:采用放射免疫法及葡萄糖氧化酶法检测对照组及GDM组空腹胰岛素(FINS)及空腹血糖(FPG)水平,采用稳态模型法计算胰岛素抵抗指数(HOMA-IR);采用免疫沉淀、western blot及增强化学发光法检测脂肪组织中IRS-1蛋白酪氨酸磷酸化程度;采用PCR扩增及其产物直接测序法检测IRS-11223丝氨酸位点基因突变。结果:①GDM组HOMA-IR为6.11±0.78,对照组为2.25±0.38,差异有统计学意义;②IRS-1蛋白质酪氨酸磷酸化程度GDM组为0.31±0.14,对照组为0.63±0.09,GDM组显著下降;③所有样本均扩增出目的片段,但未发现1例IRS-11223丝氨酸位点的基因突变。结论:GDM患者存在不同程度的胰岛素抵抗;脂肪组织IRS-1蛋白质的酪氨酸磷酸化程度降低是GDM胰岛素受体后信号传导障碍分子机制之一,参与了GDM的发病;IRS-11223丝氨酸位点的基因突变可能不是该区域GDM患者IRS-1酪氨酸磷酸化程度降低的主要机制。

The level of tyrosine phosphorylation and the relationship between it and 1223 serine sites gene mutation of insulin receptor substrate 1 in gestational diabetes mellitus

Objective:To investigate the tyrosine phosphorylation and 1223 serine sites gene mutation of insulin receptor substrate 1(IRS-1) in the adipose tissue of gestational diabetes mellitus(GDM).Methods:All samples were subjected to radioimmunoassay for fasting insulin,oxidase assay for fasting plasma glucose and steady state model method for insulin resistance index. The adipose tissue samples of all were subjected to immunoprecipitate,western blot and enhanced chemiluminescence (ECL) for tyrosine phosphorylation of insulin receptor substrate 1. Meanwhile,the IRS-1 1223 Serine Sites gene mutation of all adipose tissue samples were detected by the sequencing of PCR products.Results:The HOMA-IR of GDM group (6.11±0.78) was significant higher than those of control group (2.25± 0.38). The tyrosine phosphorylation level of IRS 1 had significant differences between GDM group (0.31±0.14) and control group (0.63±0.09). All samples were amplified by PCR assay,but no gene mutation of IRS-1 1223 serine sites was discovered by the sequencing of PCR products.Conclusion:There is varying degrees of insulin resistance in GDM. The decrease of tyrosine phosphorylation of IRS-1 in the adipose tissue of gestational diabetes mellitus may significantly contribute to the molecule mechanism for insulin resistance of GDM. The gene mutation of IRS-1 1223 serine sites may be not the chief pathogenesis of GDM in this region.