Journal of School of Public Health and

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Background and Aim: Type 2 diabetes mellitus is a heterogeneous disorder resulting from a combination of genetic and environmental factors which contribute to pathogenesis by influencing beta cell function and tissue insulin sensitivity. Protein tyrosine phosphatase 1B (PTP1B)" efficiently dephosphorylates the insulin receptor and attenuates insulin signaling. Recently, a 1484insG variant of the PTP1B gene was linked to increased risk of the metabolic syndrome in an Italian population, but this was not confirmed in subsequent studies. The purpose of this research was to investigate the association of 1484insG polymorphism of the PTP1B with obesity, insulin resistance, type 2 diabetes and other cardiovascular-related traits in an Iranian population.

Materials and Methods: The genotypes of 1484insG variant were determined by the PCR-RFLP method in 242 unrelated subjects, including 171 individuals with normal glucose tolerance and normal fasting glucose levels, and 71 type 2 diabetics. Insulin resistance was assessed using the homeostasis assessment model.

Results: The allelic frequency of the 1484insG polymorphism among type 2 diabetic patients and non-diabetic individuals was 6.3% and 3.8%, respectively (p=0.205). None of the subjects were homozygous for the 1484insG allele. Concerning quantitative traits in non-diabetic subjects, carriers of 1484insG allele had significantly higher body mass index (p=0.01), diastolic blood pressure (p=0.012), and HOMA-IR (p= 0.041) levels compared to those carrying the wild-type genotype. In type 2 diabetics, carriers of 1484insG allele had only significantly higher HOMA-B (P= 0/04) level compared to the individuals with the wild-type genotype.

Conclusion: Our results from a sample of Iranian type 2 diabetes cases and controls provide evidence that the 1484insG genotype of the PTP1B gene may be associated with obesity and insulin resistance.

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Background and Aim: Orexin is a hormone involved inoverweight and obesity and a regulator of glucose metabolism. The purpose of this study was to determine the effects of a high-intensity interval training (HIIT) on plasma levels of orexin-A (OXA) and insulin resistance in overweight women.
Materials and Methods: In a semi-experimental study, 24 overweight women (aged 20-25 years; body mass index (BMI), 25-30 kg/m²) were divided into 2 groups, namely, a control (n=12) and a training (n=12) group. The training group performed selective HIIT including 6 movements for 6 weeks (3 sessions/week). Initial and final blood markers were measured in blood samples collected 24 hours after the test. The data were analyzed using the paired and independent sample t-tests; a p<0.05 was considered to show statistical significance.
Results: There were no statistically significant differences between body weight, BMI, plasma levels of glucose, insulin and insulin resistance before and after the period in either the training or control group (p>0.05). Neither were there any significant differences between the training and control groups after the 6-week period as regards plasma levels of glucose, insulin, OXA or insulin resistance (p>0.05).
Conclusion: The findings of this study show that a 6-week high-intensity interval training has no influence on plasma OXA or insulin resistance in overweight women.