Urinary excretion of endogenous digitalis-like natriuretic substances in healthy subjects. Effect of sodium load

Abstract

In the current study digoxin-like immunoreactivity (DLIA), Na-K-ATPase inhibition and natriuretic activity of urinary extracts from 10 healthy volunteers following a low and a high-sodium intake, respectively, were measured. Detectable urinary DLIA (46.1 +/- 5.6 ng eq digoxin/day), Na-K-ATPase inhibition (182.9 +/- 22.7 nmol eq oub/day) and natriuretic activity (UNaV: 0.38 +/- 0.11 microEq/min) were observed during the low-sodium diet period in all subjects. High-sodium diet was associated with a significant increase in DLIA (87.9 +/- 9.2 ng eq digoxin/day, p less than 0.001) which parallelled changes in Na-K-ATPase inhibition (359.8 +/- 51.9 nmol eq oub/day, p less than 0.005) and natriuretic activity (UNaV: 1.33 +/- 0.3 microEq/min, p less than 0.025). These results support the contention that DLIA is related to NH.