ADM and serum lipopolysaccharide activity: Vasorelaxation might in this case rely on activation of constitutively expressed NO-synthases and/or on induction of adrenomedullin, a potent vasodilator, whose expression has been shown to be up-regulated in endotoxemia [8], the release of the vasodilator kynurenine [24] or on COX2-derived thromboxane [25].