Vascular reactivity to acetylcholine (Ach), with or without nitric oxide synthase (NOS) inhibitor NG-monomethyl-l-arginine (L-NMMA), or sodium nitroprusside (SNP) by forearm venous occlusion plethysmography and insulin sensitivity index (M mg/kg/min) in euglycemic clamp were measured in men without (n = 18, control group) or with (n = 19, metabolic syndrome group) metabolic syndrome. This evidence concerns the gene INS and metabolic syndrome.