Plasma Norepinephrine Variations with Dietary Sodium Intake

NICHOLLS, M. GARY M.B.CH.B. M.D.
KIOWSKI, WOLFGANG M.D.
ZWEIFLER, ANDREW J. M.D.
JULIUS, STEVO M.D. Sc.D.
SCHORK, M. ANTHONY PH.D.
GREENHOUSE, JOEL M.P.H.

From the Division of Hypertension, Department of Internal Medicine, Clinical Research Center, University of Michigan Medical School; and the Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan.

Supported in part by the Horace H. Rackham School of Graduate Studies and U.S. Public Health Service Grant 5 M01 RR- 42 to the Clinical Research Center, University of Michigan Medical School.

Dr. Kiowski's present address is: Department of Medicine, University of Basel, Kantonsspital, Basel, Switzerland.

Address for reprints: M. Gary Nicholls, M.D., Division of Hypertension, Box 48, R 6669 Kresge Medical Research Building, University of Michigan Medical School, Ann Arbor, Michigan48109.

Received February 19, 1979; revision accepted July 11, 1979.

Hypertension 2(1):p 29-32, January-February 1980.

SUMMARY Plasma catecholamine and renln activity levels were measured across a range of dietary sodium intakes (10-300 mEq/day) In 20 normal male volunteers. Supine plasma norepinephrine levels presented a triphasic pattern in relation to urine sodium, whereas epinephrine levels were Dot significantly altered by sodium intake, and renin showed the well-known hyperbolic relationship to urine sodium excretion. Highest supine norepinephrine values occurred at low salt intakes, the lowest when sodium excretion was between 100 and 180 mEq/day, and intermediate when sodium excretion was greater than 180 mEq/day. These findings show that sodium intake is an important consideration in the interpretation of plasma norepinephrine levels.