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Exogenous L‐arginine does not affect angiotensin II‐induced renal vasoconstriction in man
Author(s) -
Wolzt Michael,
Ugurluoglu Ara,
Schmetterer Leopold,
Dorner Guido,
Zanaschka Gabriele,
Mensik Christa,
Eichler HansGeorg
Publication year - 1998
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1046/j.1365-2125.1998.00634.x
Subject(s) - arginine , vasoconstriction , angiotensin ii , nitric oxide , medicine , renal blood flow , endocrinology , kidney , renovascular hypertension , pharmacology , chemistry , blood pressure , biochemistry , amino acid
Aims It has been suggested that provision of the substrate of nitric oxide (NO) synthesis, l‐arginine, might influence the effects of renal vasoconstrictors. We have therefore studied the effects of pretreatment or concomitant administration of l‐arginine on angiotensin II (ANG II)‐increased renovascular resistance.Methods The study was conducted in a double‐blind, randomized, cross‐over design. Eight healthy subjects were assigned to placebo or a continuous intravenous coinfusion of ANG II (5.0 ng kg −1 min −1 , infusion period 75 min) with l‐arginine (17 mg kg −1 min −1 , infusion period 30 min). Nine further subjects received a continuous infusion of ANG II with or without pretreatment of l‐arginine. Changes in renal plasma flow (RPF) were estimated by the steady state clearance of PAH.Results l‐arginine alone increased RPF to 110±10% over baseline ( P <0.003). The ANG II‐induced decrease in RPF was not affected by pretreatment or coinfusion of l‐arginine.Conclusions Our results demonstrate that a counterregulatory response of the renal vasculature to high levels of ANG II does not depend on exogenous l‐arginine. In healthy subjects, this lack of functional antagonism at the renal vasculature is therefore not a result of NO substrate availability.