This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted 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 Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by EISENHOFER, G. Articles by GOLDSTEIN, D. S. Search for Related Content PubMed PubMed Citation Articles by EISENHOFER, G. Articles by GOLDSTEIN, D. S.

Plasma Dihydroxyphenylalanine and Total Body and Regional Noradrenergic Activity in Humans

Clinical Neuroscience Branch, National Institute of Neurological and Communicative Disorders and Stroke (G.E., I.J.K), and Cardiology (J.E.B., R.O.C.) and Hypertension-Endocrine (D.S.G., R.S.) Branches, National Heart, Lung, and Blood Institute, National Institutes of Health Bethesda, Maryland 20892

Address all correspondence and requests for reprints to: Dr. Graeme Eisenhofer, Baker Medical Research Institute, Commercial Road, Prahran, Victoria 3181, Australia.

Dihydroxyphenylalanine (DOPA) is the immediate product of the rate-limiting step in catecholamine biosynthesis, hydroxylation of tyrosine. This study examined whether plasma concentrations of DOPA are related to tyrosine hydroxylase activity. Plasma concentrations of DOPA, norepinephrine, and the norepinephrine metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured in arterial blood and blood draining the heart, brain, and forearm of 21 patients undergoing cardiac catheterization. Rates of entry of norepinephrine into arterial plasma and plasma draining the heart were estimated using infusions of radioactive norepinephrine. Arterial plasma DOPA correlated positively with arterial plasma DHPG (r = 0.63), MHPG (r = 0.47), norepinephrine (r = 0.67), and the rate of entry of norepinephrine into arterial plasma (r = 0.62). There were significant arteriovenous increments in plasma DOPA: 28% across the heart, 18% across the brain, and 32% across the forearm. Arteriovenous increments in plasma DOPA across the brain correlated positively with increments in plasma DHPG (r = 0.83), but not with increments in norepinephrine or MHPG. In the arm, where MHPG was the major metabolite, arteriovenous increments in DOPA correlated positively with increments in MHPG (r = 0.52) and with the combined increments in MHPG, DHPG, and norepinephrine (r = 0.60). In the heart, where DHPG was the major metabolite, arteriovenous increments in DOPA correlated positively with increments in DHPG (r = 0.72) and the combined increments in DHPG, MHPG, and norepinephrine (r = 0.62). The rate at which norepinephrine entered the great cardiac venous plasma from tissues of the heart correlated positively with the rate at which DOPA overflowed from the heart into the systemic circulation (r = 0.56). The relationships between plasma DOPA and norepinephrine metabolism and the rates of norepinephrine entry into plasma support the view that plasma DOPA reflects tyrosine hydroxylase activity.

Received May 25, 1988.

This article has been cited by other articles:

				C. J. Tack, P. J. van Gurp, C. Holmes, and D. S. Goldstein Local Sympathetic Denervation in Painful Diabetic Neuropathy Diabetes, December 1, 2002; 51(12): 3545 - 3553. [Abstract] [Full Text] [PDF]

				D. S. Goldstein, D. Robertson, M. Esler, S. E. Straus, and G. Eisenhofer Dysautonomias: Clinical Disorders of the Autonomic Nervous System Ann Intern Med, November 5, 2002; 137(9): 753 - 763. [Abstract] [Full Text] [PDF]

				D. S. Goldstein, C. Holmes, S.-T. Li, S. Bruce, L. V. Metman, and R. O. Cannon III Cardiac Sympathetic Denervation in Parkinson Disease Ann Intern Med, September 5, 2000; 133(5): 338 - 347. [Abstract] [Full Text] [PDF]

				D. S. Goldstein, K. J. Swoboda, J. M. Miles, S. W. Coppack, A. Aneman, C. Holmes, I. Lamensdorf, and G. Eisenhofer Sources and Physiological Significance of Plasma Dopamine Sulfate J. Clin. Endocrinol. Metab., July 1, 1999; 84(7): 2523 - 2531. [Abstract] [Full Text]

				G. Eisenhofer, P. Friberg, B. Rundqvist, A. A. Quyyumi, G. Lambert, D. M. Kaye, I. J. Kopin, D. S. Goldstein, and M. D. Esler Cardiac Sympathetic Nerve Function in Congestive Heart Failure Circulation, May 1, 1996; 93(9): 1667 - 1676. [Abstract] [Full Text]

				K. Kobayashi, S. Morita, H. Sawada, T. Mizuguchi, K. Yamada, I. Nagatsu, T. Hata, Y. Watanabe, K. Fujita, and T. Nagatsu Targeted Disruption of the Tyrosine Hydroxylase Locus Results in Severe Catecholamine Depletion and Perinatal Lethality in Mice J. Biol. Chem., November 10, 1995; 270(45): 27235 - 27243. [Abstract] [Full Text] [PDF]