Samples of cord serum from 29 healthy neonates were analysed for digoxin-like immunoreactive substance (DLIS), cortisol, 17β-oestradiol, progesterone, dehydroepiandrosterone-sulphate (DHEAS), 17α-hydroxyprogesterone (17OHP), androstenedione, oestriol and ouabain-like activity (OLA; by inhibition of Na+,K+ ATPase activity). The mean serum concentration of DLIS was 0·91 (SD = 0·19) nmol/L and the mean OLA was 26·1 (SD = 11·5) nmol/L. There was no correlation between DLIS and OLA. DLIS correlated significantly with oestriol (r = 0·521), progesterone (r = 0·534) and 17OHP (r = 0·43). Stepwise multiple regression analysis showed that 17β-oestradiol, progesterone and androstenedione contributed to DLIS and the intercept was 0·64 (SD = 0·127). The concentrations of steroids (17β-oestradiol, progesterone, androstenedione) required to displace digoxin by 50% in the digoxin immunoassay and inhibit Na+,K+ ATPase in the OLA assay were 103–104-fold higher than those found in cord serum. We conclude that the contribution of these steroids to DLIS is small and that DLIS and OLA measure different compounds.
GravesSWValdesRJrBrownBAKnightABCraigHR. Endogenous digoxin immunoreactive substances in human pregnancies. J Clin Endocrinol Metab1984; 58: 748–51.
2.
KrivoyNJakobiPPaldiEAeroyG.Total digoxin-like immunoreactive factor(s) in healthy population, uncomplicated term pregnancies and neonate. J Endocrinol Invest1990; 13: 9–12.
3.
ValdesRJrGravesSWBrownBLandtM.Endogenous substance in new born infants causing false positive digoxin measurements. J Pediatr1983; 102: 947–50.
4.
PudekMRSeccombeDWWhitefieldMFLingE.Digoxin like immunoreactivity in premature and full term infants not receiving digoxin therapy. N Engl J Med1983; 308: 904–5.
5.
DiamandesEPPapanastasiou-DiamandiASoldinSJ. Digoxin immunoactivity in cord and maternal serum and placental extracts. Partial characterization of immunoreactive substances by high performance liquid chromatography and inhibition of Na+,K+ ATPase. Clin Biochem1985; 18: 48–55.
6.
SeccombeDWPudekMRWhitfieldMFWhittmanBFKingJF. Perinatal changes in a digoxin-like immunoreactive substance. Paediatric Res1984; 18: 1097–9.
7.
EbaraHSuzukiSNagashimaKShimanoSKuroumeT.Digoxin like immunoreactive substances in urine and serum from preterm and term infants: Relationship to renal excretion of sodium. J Pediatr1986; 108: 760–2.
8.
ScherrmannJMSandoukPGuedeneyX.Specific interaction between antidigoxin antibodies and digoxin-like immunoreactive substances in cord serum. Clin Chem1986; 32: 97–100.
9.
GonzalesARPhelpsSJCohranEBSibaiBM. Digoxin-like immunoreactive substance in pregnancy. Am J Obstet Gynecol1987; 157: 660–4.
10.
GravesSVBrownBValdesR.Digoxin-like substance in patients with renal impairment. Ann Intern Med1983; 96: 604–8.
11.
VasdevSJohnsonELongerichLPrabhakaranMGaultMH. Plasma endogenous digitalis like factors in healthy individuals and in dialysis dependent and kidney transplant patients. Clin Nephrol1987; 27: 169–74.
12.
KellyRAO'HaraDSMitchWEEndogenous digitalis-like factors in hypertension and chronic renal insufficiency. Kidney Int1986; 30: 723–9.
ShiloLShapiroMSDolevSShenkmanL.Endogenous digoxin like material in patients with liver disease. Ann Intern Med1985; 103: 643.
15.
DerayGRieuMDevynekMAEvidence of an endogenous digitalis-like factor in the plasma of patients with acromegaly. N Engl J Med1987; 316: 575–9.
16.
WijdicksEFMVermeulenMVan BrummelenPden BoerNCvan GijnJ.Digoxin-like immunoreactive substance in patients with aneurysmal subarachnoid haemorrhage. BMJ1987; 294: 729–32.
17.
GhioneSBalzanSMontaliUPlasma digoxin-like immunoreactivity in essential hypertension: Relation to plasma renin activity. J Hypertension1983; 1 (Suppl 2): 142–4.
18.
BalzanSMontaliUGanovesi-EbertABiverPFantoniMGhioneS.Comparison between endogenous digoxin-like immunoreactivity and 86Rb uptake by erythrocytes in extracts of human plasma. Clin Sci1989; 77: 375–81.
19.
BalzanSClaricoAdel ChiccaM GarciaMontaliVGhioneS.Digoxin like immunoreactivity in normal plasma and urine as detected by a solid-phase radioimmunoassay. Clin Chem1984; 30: 450–1.
20.
ShiloLWerberMMDolevSShapiroMShenkmanL.Digoxin-like immunoreactivity: Occurrence in molecular forms and partial characterization. J Clin Endocrinol Metab1987; 64: 1257–60.
21.
VingeEEkmanR.Partial characterization of endogenous digoxin-like substance in human urine. Ther Drug Monit1988; 10: 8–15.
22.
FriedmanHSAbramowitzTNguyenBUrinary digoxin-like immunoreactive substance in pregnancy. Relation to urinary electrolytes. Am J Med1987; 83: 261–4.
23.
BuckalewVMJrPaschal-McCormickK.Natriuretic hormone: Current status. Am J Nephrol1989; 9: 329–42.
24.
ToselandPAOldfieldPRMurphyGMLawsonAM. Tentative identification of a digoxin-like immunoreactive substance. Ther Drug Monit1988; 10: 168–71.
25.
VasdevSCLongerichLLIttelTHJohnsonEBarrowmanJAGaultMH. Bile salts as endogenous digitalis-like factors. Clin Invest Med1986; 9: 201–8.
26.
HiranoTOkaKNaitohTHosakaKMitsuhashiH.Endogenous digoxin-like activity of mammalian-lignans and their derivatives. Res Comm Chem Pathol Pharmacol1989; 64: 227–40.
27.
HratowichMLabellaF.Endogenous digitalis-like factors: in vitro comparison of biological and immunological activities of peptide and steroid candidates. Eur J Pharmacol1984; 106: 567–75.
28.
VasdevSLongrichLJohnsonEBrentDGaultMH. Dehydroenpiandrosterone sulphate as a digitalis-like factor in plasma of healthy human adults. Res Comm Chem Pathol Pharmacol1985; 49: 387–99.
29.
VingeEHelgesen-RosendalSBackstromT.Progesterone, some progesterone derivatives and urinary digoxin-like substances from pregnant woman in radioimmuno- and 86Rb-uptake assays of digoxin. Pharmacol Toxicol1988; 63: 277–80.
30.
PudekMRSeccombeDWHumphriesKH. HPLC fractionation of digoxin-like immunoreactive substances in neonatal cord-blood and meconium and adult urine and bile. Clin Biochem1985; 18: 202.
31.
SeccombeDWPudekMRNowaezynskiWHumphriesKH. Digoxin-like immunoreactivity, displacement of ouabain and inhibition of Na+/K+ ATPase by four steroids known to be increased in essential hypertension. Clin Biochem1989; 22: 17–21.
32.
GotoAYamadaKIshiiMYoshiokaMSugimotoT.Is dehydroepiandrosterone sulfate a natriuretic digitalis-factor in human serum?Clin Chim Acta1990; 192: 145–51.
33.
LauBWValdesRJr.Criteria for identifying endogenous compounds as digoxin-like immunoreactive factors in humans. Clin Chim Acta1988; 175: 67–77.
34.
PudekMRSeccombeDWJacobsonBEWhitfieldMF. Seven different digoxin immunoassay kits compared with respect to interference by a digoxin-like immunoreactive substance in serum from premature and full-term infants. Clin Chem1983; 29: 1972–4.
35.
DorisPAStoccoDM. An endogenous digitalis-like factor derived from the adrenal gland: Studies of adrenal tissue from various species. Endocrinology1989; 125: 2573–9.
36.
TamuraMLamTTInagamiT.Isolation and characterization of a specific endogenous Na+,K+ ATPase inhibitor from bovine adrenal. Biochemistry1988; 27: 4244–53.
37.
ChasalowFIBlethenSC. Characterization of digoxin-like materials in human cord serum. Ann N Y Acad Sci1990; 591: 212–21.
38.
SeccombeDWPudekMRHumphriesKHA study into the nature and organ source of digoxin-like immunoreactive substance(s) in the perinatal period. Biol Neonate1989; 56: 136–46.
39.
LongerichLJohnsonRBrentDGaultMH. Plasma conjugated androgens in a dialysis-dependent male as immunoreactive digitalis-like factors. Clin Nephrol1990; 34: 72–8.
