Dehydroepiandrosterone sulfate as a digitalis like factor in plasma of healthy human adults.

Plasma values for digitalis like factors (DLF) and dehydroepiandrosterone sulfate (DHEA-S) in 11 healthy adults were (mean +/- SD) 44 +/- 6 pmol digoxin equivalents/L and 11 +/- 3 mumol/L respectively. DHEA-S accounted for 62-100% of the total plasma DLF. DHEA-S and plasma DLF displaced [125I]digoxin from digoxin antibody, inhibited hog brain Na,K-ATPase and displaced [3H]ouabain from ATPase in a concentration dependent manner similar to digoxin. Plasma extracts (11 subjects) inhibited Na,K-ATPase and displaced [3H]ouabain from Na,K-ATPase with mean values +/- SD of 1.7 +/- 0.22 and 1.8 +/- 0.25 nmol digoxin equivalents/L plasma respectively. HPLC fractionation of plasma DLF showed several peaks. The major peak was due to DHEA-S, identified by its retention time, radioimmunoassay of DHEA-S and mass spectrometry.