INS and type 2 diabetes mellitus: However, since, starting from the 5th decade in men, endothelium- (NO-) dependent vasodilation with acetylcholine, after arterial occlusion or upon insulin/feeding are clearly attenuated with age, the metabolic syndrome or type-2-diabetes [3, 25, 28, 39], NO-dependent mechanism are likely to, at least in part, play a role in the presently shown age-related microvascular dysfunction during exercise in middle-aged males.