Host: The Japanese Society of Toxicology
Endogenous digitalis-like factor (EDLF) obtained from maternal and umbilical cord plasma at delivery were measured by fluorescence polarization immunoassay (FPIA). In each sample, concentrations of dehydroepiandrosterone, dehydroepiandrosterone sulfate, estradiol, estriol, hydrocortisone, progesterone, and testosterone were measured by radioimmunoassay, and cross-reaction tests of digitalis-like immunoreactive substances (DLIS) with these substances were performed. By FPIA, the concentration of DLIS in umbilical cord plasma (0.55±0.22 ng/mL) was significantly higher than that in maternal plasma (0.23±0.11 ng/mL). In the cross-reaction tests, when the concentration of dehydroepiandrosterone sulfate was higher than 1.0 μg/mL or that of progesterone was higher than 0.5 μg/mL, DLIS were detected by FPIA. By radioimmunoassay, there was no significant difference in the dehydroepiandrosterone sulfate concentration between the maternal plasma (2,917±1,001 ng/mL) and the umbilical cord plasma (1,957±376 ng/mL). The progesterone concentration in the umbilical cord plasma (310.0±85.7 ng/mL) was significantly higher than that in the maternal plasma (126.4±38.5 ng/mL). These results suggest that dehydroepiandrosterone sulfate in maternal plasma and progesterone in maternal and umbilical cord plasma can be measured as digoxin by FPIA, which might be EDLF.
