Effects of high altitude exposure on plasma and urinary digoxin-like immunoreactive substance

Six young healthy subjects underwent a 20 day exposure to altitude, at 4930 m (16, 174 ft), to evaluate possible plasma and urine digoxin-like immunoreactive substance (DLIS) changes accompanying the altered water and electrolyte balance induced by hypoxia. We studied DLIS, plasma renin activity (PRA), aldosterone, atrial natriuretic peptide (ANP), and arginine vasopressin (ADH) in serial blood and urine samples. An increase in DLIS in plasma (P <.005) and urine (P <.01) was found, while aldosterone was decreased (P <.02). PRA, ADH, and ANP did not change significantly. A trend to a greater loss of sodium through urinary excretion, correlated with urinary DLIS values (r = 0.47, P <.01), was observed. Data suggest a possible important role of DLIS in adaptive response of human organism to high altitude. © 1992 by the American Journal of Hypertension, Inc.