Endothelial nitric oxide synthase (eNOS) gene Glu298Asp polymorphism in patients with noninsulin-dependent Diabetes Mellitus

The aim of our study is to determine the frequency of eNOS gene Glu298Asp polymorphism in patients with Type 2 diabetes (T2DM) and to determine the effects of Glu298Asp genotypes (Glu/Glu, Glu/Asp, Asp/Asp) on insulin related phenotypes and serum lipids.The study has been performed on 115 patients (67 Men, 48 Women) with T2DM and 68 healthy individuals (47 Men, 21 Women) proven not to have T2DM with clinical diagnosis methods. eNOS gene Glu298Asp genotypes were determined with polymerase chain reaction and restriction fragment length polymorphism methods. The eNOS gene Glu298Asp genotypes have been compared with respect to insulin related phenotypes and serum lipid parameters.The frequencies of eNOS gene Glu298Asp genotypes were found to be % 13.0 for Glu/Glu, % 49.6 for Asp/Asp and %37.4 for Glu/Asp in the T2DM group and % 16.2 for Glu/Glu, % 41.2 for Asp/Asp, %42.6 for Glu/Asp in the control group. No significant difference was observed for eNOS Glu298Asp genotype frequencies when T2DM and control groups were compared. A significant difference (p?0.001) was observed for fasting glucose, insulin, HbA1c, insulin resistance, hepatic insulin sensitivity (HIS) and ß-cell index (HOMA) levels when T2DM and control groups were compared. In T2DM group patients with Asp/Asp genotype were found to have lower HIS levels in comparison to Glu/Glu. In healthy controls, the insulin and HOMA levels were found to be lower in Asp/Asp genotype with respect to Glu/Glu genotype carriers. Also, in type 2 diabetic patients with Asp/Asp genotype, visceral obesity was found to be higher in comparison to Glu/Glu genotype. eNOS Glu298Asp polymorphism was not found to affect serum lipid levels in T2DM group. However in the healthy control group, lower serum apoB levels have been observed in Asp/Asp genotype when compared to Glu/Glu genotype carriers (p?0.05).Key Words: eNOS, Glu298Asp, Type 2 diabetes, hepatic insulin sensitivity, HOMA