[Relations between endothelial nitric oxide synthase and angiotensin-converting gene polymorphisms and certain biochemical parameters in patients with cardiac syndrome X]. 
Cardiological syndrome X (CSX) is defined as effort anginal pain, positive exercise tolerance test and absence of angiographically documented stenosis in coronary arteries.  Some genetic predispositions and metabolic disturbances can participate in development of this syndrome.  The aim of our study was to investigate the associations between some biochemical parameters and polymorphism of ACE and eNOS (VNTR and Glu298Asp) genes in patients with CSX.  36 patients with CSX and a control group of 30 healthy volunteers were included in the study.  The genotypes were determined by the polymerase chain reaction.  Our study revealed that patients with CSX exerted lower fasting NOx levels, tended to have higher insulin values measured at 1 h of oral glucose tolerance test and higher levels of triglycerides and free fatty acids during oral lipid tolerance test.  Patients with genotype T/T Glu298Asp of eNOS and 4/4 VNTR of eNOS revealed lower levels of NOx compared to patients with genotypes G/G and 5/5, respectively (30.5 +/- 7.2 vs 13.2 +/- 4.5; 28.6 +/- 8.4 vs 14.2 +/- 7.4; p<0.05).  Thus, we conclude that disturbances in free fatty acid utilization, estimated by postprandial lipaemic test play important roles in the development of endothelial injury in CSX.