When compared with controls, the serum level of MCP-1, TNF-<i>α</i>, IL-6, IRS-1, and p-IRS-1 was significantly increased in T2DM rats, but the level of PKB, p-PKB, PI3Kp85, and p-PI3K expression was reduced (<i>P</i> < 0.05).
When compared with cells from control subjects, myotubes established from patients with type 2 diabetes presented the same defects as those previously evidenced in vivo in muscle biopsies, including defective stimulation of phosphatidylinositol (PI) 3-kinase activity, decreased association of PI 3-kinase with insulin receptor substrate (IRS)-1 and reduced IRS-1 tyrosine phosphorylation during insulin stimulation.
Western blot analysis indicated that the up-regulated IRS1-PI3K-Akt phosphorylation followed by the down-regulated FoxO1/GSK 3β phosphorylation contributed to the enhanced glycogen synthesis and the decreased gluconeogenesis by GXG, suggesting that the response of insulin-mediated IRS1-PI3K-Akt-FoxO1/GSK 3β signaling to GXG might be the required mechanism for GXG-ameliorated development of type 2 diabetes.
We suggest that our results provide strong evidence that variation in the IRS1 and TCF7L2 genes confers susceptibility to T2D in our studied populations.
We studied possible relations between GDM and both insulin receptor substrate 1 (IRS-1) (Gly972Arg) and beta3-adrenergic receptor (ADRB3 Trp64Arg, beta3-AR) gene mutations, considered potential modifying factors in the etiology of type 2 diabetes mellitus.
We investigated the possible association between insulin receptor substrate-1 (IRS-1) polymorphisms and high platelet reactivity in coronary artery disease (CAD) patients with type 2 diabetes mellitus (T2DM).
We have genotyped three single nucleotide polymorphisms associated with type 2 diabetes in a large type 1 diabetic family collection of European descent: Gly972Arg in the insulin receptor substrate 1 (IRS1) gene, Glu23Lys in the potassium inwardly-rectifying channel gene (KCNJ11), and Pro12Ala in the peroxisome proliferative-activated receptor gamma2 gene (PPARG2).
We have demonstrated that 13 variants confer an increased risk of type 2 diabetes in our Pakistani populations; to our knowledge this is the first time that SNPs in or near KCNQ1, JAZF1, IRS1, KLF14, CHCHD9 and DUSP9 have been significantly associated with the disease in South Asians.
We have analyzed the association of variants in the genes for amylin, insulin receptor, insulin receptor substrate-1 (IRS-1), and coagulation factor V with type 2 diabetes mellitus.
We conducted an exploratory analysis by testing whether common genetic variability at IRS1, ENPP1 and TRIB3 loci is associated with cardiovascular risk traits and metabolic phenotypes in T2DM.
We conclude that the tandem repeat polymorphism in the glycogen synthase gene and the polymorphisms at codons 513 and 972 of the IRS-1 gene are not associated with a higher risk for the development of NIDDM in Japanese subjects.
Unlike previously reported T2D risk loci, which predominantly associate with impaired beta cell function, the C allele of rs2943641 was associated with insulin resistance and hyperinsulinemia in 14,358 French, Danish and Finnish participants from population-based cohorts; this allele was also associated with reduced basal levels of IRS1 protein and decreased insulin induction of IRS1-associated phosphatidylinositol-3-OH kinase activity in human skeletal muscle biopsies.
Unlike previously reported T2D risk loci, which predominantly associate with impaired beta cell function, the C allele of rs2943641 was associated with insulin resistance and hyperinsulinemia in 14,358 French, Danish and Finnish participants from population-based cohorts; this allele was also associated with reduced basal levels of IRS1 protein and decreased insulin induction of IRS1-associated phosphatidylinositol-3-OH kinase activity in human skeletal muscle biopsies.
Two mutations of the IRS-1 gene (Gly(972)Arg and Ala(513)Pro) have been described, although their roles in the development of insulin resistance and non-insulin-dependent diabetes mellitus (NIDDM) remain controversial.
Two IRS1 variants (rs7578326 and rs2943641) identified by genome-wide association studies as related to type 2 diabetes were tested for their associations with IR and related traits and interaction with diet in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study (n = 820) and the Boston Puerto Rican Health Study (BPRHS) (n = 844).
To replicating the associations of type 2 diabetes (T2D) and six novel reported variants in Han Chinese lean individuals of first episode T2D, a total of six high risk single nucleotide polymorphisms (SNPs) from the BCL11A, DUSP9, IRS1, CENTD2, ADRA2A, and CDKAL1 genes were examined.
To determine whether variation in the Irs-1 contributes to genetic susceptibility to type 2 diabetes in Turkish people, PCR-RFLP and DNA sequencing method were utilized to analyze the coding region of Irs-1 in 70 subject and 116 control patients.
To determine whether variation in the IRS-1 gene contributes to genetic susceptibility to insulin resistance and Type 2 diabetes in Mexican Americans, the entire coding region of the IRS-1 gene was screened for variation in 31 unrelated subjects with Type 2 diabetes using single-stranded conformational polymorphism analysis (SSCP) and dideoxy sequence analysis.
Thus, we were able to replicate the earlier findings of an association between the IRS-1 Arg(972) variant and secondary failure to sulphonylurea drugs, and further observed a general association between HbA1c and this polymorphism in type 2 diabetes patients treated with insulinotropic hypoglycaemic drugs but not with metformin.