Na/K ATPase inhibition by digitalis-like factors in neonates

Conference · Sat Mar 01 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5388937

Bottorff, M B; Songu-Mize, E; Hoon, T J; Phelps, S J; Kamper, C A

At the authors institution, 48% of neonates < 1 month of age had false-positive digoxin immunoassay determinations while not receiving digoxin, presumably due to an endogenous digoxin-like immunoreactive substance (DLIS) in the plasma. Plasma from 3 neonates positive for DLIS by fluorescence polarization immunoassay (FPIA) was evaluated for inhibitory activity on human red blood cell (RBC) Na/K ATPase. Neonatal plasma aliquots containing DLIS concentrations (conc) of 0.24, 0.37, 0.43, 0.49 and 0.61 ng/ml (3.07 - 7.81 x 10/sup -10/M) were incubated with human RBC and /sup 86/Rb in order to measure /sup 86/Rb uptake inhibition with respect to DLIS negative neonatal plasma. /sup 86/Rb uptake inhibition by digoxin-spiked human serum (1.07 x 10/sup -10/ - 4.57 x 10/sup -6/M) was also measured. Percent inhibition vs. log molar conc plots for DLIS and digoxin were compared. DLIS inhibited Na/K ATPase in a linear fashion over the range studied. Comparing the linear portions of the conc-inhibition curves for digoxin and DLIS, the molar conc of digoxin producing 40% inhibition of /sup 86/Rb uptake is 333 times greater than the molar conc of DLIS producing similar inhibition. Therefore, DLIS in neonatal serum as measured by FPIA has approximately 300 times greater inhibitory activity than digoxin. The presence of circulating DLIS may reflect an adaptive or maladaptive response to some, as yet unknown, process early in life.

• Research Organization: Univ. of Tennessee, Memphis
• OSTI ID: 5388937
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALKALI METAL ISOTOPES
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLASMA
BODY FLUIDS
DAYS LIVING RADIOISOTOPES
DIGITALIS
ENZYME ACTIVITY
ENZYMES
ERYTHROCYTES
FLUORESCENCE
HYDROLASES
IMMUNE REACTIONS
INHIBITION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LUMINESCENCE
MAMMALS
MAN
MATERIALS
MEDICINAL PLANTS
MINUTES LIVING RADIOISOTOPES
NEONATES
NUCLEI
ODD-ODD NUCLEI
PHOSPHOHYDROLASES
PLANTS
PRIMATES
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
TRACER TECHNIQUES
VERTEBRATES