This Article Full Text Full Text (PDF) All Versions of this Article: 41/6/1336    most recent 01.HYP.0000070024.59313.AEv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chin-Dusting, J. P.F. Articles by Whitworth, J. A. Search for Related Content PubMed PubMed Citation Articles by Chin-Dusting, J. P.F. Articles by Whitworth, J. A. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB (L)-ARGININE HYDROCORTISONE Related Collections Other hypertension Clinical Studies Endothelium/vascular type/nitric oxide

(Hypertension. 2003;41:1336.)
© 2003 American Heart Association, Inc.

Scientific Contributions

L-Arginine Transport in Humans With Cortisol-Induced Hypertension

Jaye P.F. Chin-Dusting; Belinda A. Ahlers; David M. Kaye; John J. Kelly; Judith A. Whitworth

From the Alfred and Baker Medical Unit, Wynn Domain, Baker Heart Research Institute and Alfred Hospital (J.P.F.C.-D., B.A.A., D.M.K.), Prahran; the Department of Renal Medicine and Medicine, St George Hospital, University of New South Wales (J.J.K.), Kogarah; and the John Curtin School of Medical Research, Australian National University (J.A.W.), Canberra, Australia.

Correspondence to Jaye Chin-Dusting, Baker Heart Research Institute, PO Box 6492, St Kilda Rd Central, Victoria 8008, Australia. E-mail j.chin{at}alfred.org.au

A deficient L-arginine–nitric oxide system is implicated in cortisol-induced hypertension. We investigate whether abnormalities in L-arginine uptake contribute to this deficiency. Eight healthy men were recruited. Hydrocortisone acetate (50 mg) was given orally every 6 hours for 24 hours after a 5-day fixed-salt diet (150 mmol/d). Crossover studies were performed 2 weeks apart. Thirty milliliters of blood was obtained for isolation of peripheral blood mononuclear cells after each treatment period. L-Arginine uptake was assessed in mononuclear cells incubated with L-arginine (1 to 300 µmol/L), incorporating 100 nmol/L [³H]-L-arginine for a period of 5 minutes at 37°C. Forearm [³H]-L-arginine extraction was calculated after infusion of [³H]-L-arginine into the brachial artery at a rate of 100 nCi/min for 80 minutes. Deep forearm venous samples were collected for determination of L-arginine extraction. Plasma cortisol concentrations were significantly raised during the active phase (323±43 to 1082±245 mmol/L, P<0.05). Systolic blood pressure was elevated by an average of 7 mm Hg. Neither L-arginine transport into mononuclear cells (placebo vs active, 26.3±3.6 vs 29.0±2.1 pmol/10 000 cells per 5 minutes, respectively, at an L-arginine concentration of 300 µmol/L) nor L-arginine extraction in the forearm (at 80 minutes, placebo vs active, 1 868 904±434 962 vs 2 013 910±770 619 disintegrations per minute) was affected by cortisol treatment; ie, that L-arginine uptake is not affected by short-term cortisol treatment. We conclude that cortisol-induced increases in blood pressure are not associated with abnormalities in the L-arginine transport system.

Key Words: cortisol • hypertension, mineralocorticoid • nitric oxide • arginine • human