RESUMO
Background: Nitric oxide (NO) is a potent vasodilator synthesized by the vascular endothelium. It has been reported that endothelial nitric oxide synthase (eNOS) Glu298Asp gene polymorphism is associated with coronary artery disease (CAD). Methodology: In this study, we investigated Glu298Asp eNOS polymorphism and serum NO in a group of 146 age-matched male subjects; 77 patients with coronary artery disease (CAD) classified according to the severity of coronary insufficiency and 69 normal male controls. Results: The obtained frequencies of the eNOS Glu298Asp genotypes for the CAD subjects were GG (54.5%), GT (31.20%), and TT (14.3%). The allele distributions of G and T were 70.1 and 29.9%, respectively. In the control group, the genotype frequencies were 53.6% for GG, 36.2% for GT, and 10.2% for TT, and the frequencies of the G and T alleles were 71.7% and 28.3%, respectively. There were no significant differences in genotype and allele frequencies between the CAD patients and the control group. The mean serum NO levels in CAD patients was significantly higher than that of healthy subjects (p=0.0139). Conclusion: No significant association was detected when CAD severity, genotypes and NO serum levels were correlated.