Urinary 20-hydroxyeicosatetraenoic acid excretion is associated with oxidative stress in hypertensive subjects

Oxidative stress has been implicated in the pathogenesis of hypertension. 20-Hydroxyeicosatetraenoic acid (20-HETE) is a cytochrome P450 product of arachidonic acid metabolism, thought to be involved in the regulation of blood pressure (BP). The metabolism of arachidonic acid by cytochrome P450 enzymes may be a significant source of oxidative stress. F 2-isoprostanes are reliable markers of in vivo oxidative damage. γ-Glutamyl transpeptidase (γ-GT) has traditionally been associated with alcohol intake or liver dysfunction and may be an early marker of oxidative stress. The objective of the present study was to investigate relationships between 20-HETE excretion and markers of oxidative stress (F 2-isoprostanes and γ-GT). Sixty-nine treated hypertensive subjects underwent measurement of 24-h ambulatory BP, serum γ-GT, and urinary F 2-isoprostane and 20-HETE excretion. 20-HETE excretion was positively associated with 24-h diastolic BP ( p = 0.005), alcohol intake ( p = 0.008), γ-GT ( p = 0.007), and F 2-isoprostanes ( p = 0.005). F 2-isoprostanes were positively associated with alcohol intake ( p = 0.018) and γ-GT ( p = 0.01). In a multivariate regression, γ-GT remained an independent predictor of 20-HETE excretion, after adjustment for age, gender, BMI, and alcohol intake. In conclusion, the study highlights the positive association observed between 20-HETE excretion and markers of oxidative damage. The study also provides evidence that γ-GT may be a useful marker of oxidative stress.