Impaired l-Arginine Transport and Endothelial Function in Hypertensive and Genetically Predisposed Normotensive Subjects

Background— Impaired endothelium-dependent NO-mediated vasodilation is a key feature of essential hypertension and may precede the increase in blood pressure. We investigated whether transport of the NO precursor l-arginine is related to decreased endothelial function. Methods and Results— Radiotracer kinetics ([3H]l-arginine) were used to measure forearm and peripheral blood mononuclear cell arginine uptake in hypertensive subjects (n=12) and in 2 groups of healthy volunteers with (n=15) and without (n=15) a family history of hypertension. In conjunction, forearm blood flow responses to acetylcholine and sodium nitroprusside were measured before and after a supplemental intra-arterial infusion of l-arginine. In vivo and in vitro measures of l-arginine transport were substantially reduced in the essential hypertension and positive family history groups compared with the negative family history group; however, no difference was detected in peripheral blood mononuclear cell mRNA or protein expression levels...