Arachidonic acid metabolism-derived products are key mediators of angiotensin II-mediated vascular effects. The modulatory effect of cyclooxygenase derived products--in particular thromboxane A2 and prostaglandin H2--in angiotensin II-mediated vascular effects is well established. In contrast, few studies have assessed the involvement of lipoxygenase-derived products in the vascular effects of angiotensin II. Cysteinyl leukotrienes (5-lipoxygenase-derived products) and 12-hydroxyeicosatetraenoic acids (12-HETE) (12-lipoxygenase-derived products) are potent proinflammatory and vasomotor mediators. Their biosynthesis is increased in various models of hypertension. In addition, compelling evidence has suggested that they might contribute to the vasoconstrictor, hypertrophic and mitogenic effects of angiotensin II. The demonstration of their contribution to angiotensin II-mediated vascular effects may explain, at least in part, the vascular inflammatory complications associated with hypertension.