Release of a Substance From the Human Placenta Having Digoxin‐like Immunoreactivity

Abstract

1. The human placental lobule, perfused with a constant flow (5 mL/min) of Krebs' solution after delivery at term, released into the fetal perfusate a digoxin-like substance, as measured by a fluorescence polarization immunoassay. 2. Initially the venous concentration was 360 +/- 66.7 pmol/L digoxin equivalents. This level did not change significantly during fetal vasoconstriction induced by prostaglandin F2 alpha infusion and persisted for the duration of the experiment (1.5-2 h). 3. Infusion into the fetal circulation of Fab fragments of sheep antibodies to digoxin caused vasodilatation, indicated by a fall in perfusion pressure. 4. Thus a digoxin-like immunoreactive substance, previously reported to be present in the placenta, is released into the fetal circulation and may play a role in placental control of fetal vascular tone.

Endogenous Cardiotonic Steroids: Physiology, Pharmacology, and Novel Therapeutic Targets

“…The mechanism underlying this effect is believed to be cross-reactivity with endogenous CTS. These clinical observations are in agreement with the results of an experimental study, which demonstrated a vasorelaxant action of Digibind in isolated perfused preeclamptic placentae (Di Grande et al, 1993). Accordingly, the Na + /K + -ATPase from preeclamptic placentae was shown to be up-regulated and to exhibit heightened sensitivity to digitalis glycosides (Amler et al, 1994).…”

Autacoids and Control of Human Placental Blood Flow

“…Among substances released from the placenta into the fetal venous effluent are those, so far unidentified, which show digoxin-like immunoreactivity (Di Grande et al 1993). Digoxin-like immunoreactive substances (DLIS) appear in both maternal and fetal blood during pregnancy, with levels being highest during the third trimester (Valdes 1985).…”

Interaction of Digibind with endogenous cardiotonic steroids from preeclamptic placentae

“…Since the placenta is a likely source of CTS [16,17], the goals of our study were to compare the levels of MBG and EO in preeclamptic and normal placentae, and to study the ability of Digibind to interact with MBG and ouabain-immunoreactive material purified from normal and preeclamptic placentae via reverse-phase high performance liquid chromatography (HPLC).…”