title: Characterization of ouabain-like immunoreactivity in human urine.
abstract: OBJECTIVE
  To characterize ouabain-like immunoreactivity in human urine.
  
  
  METHODS
  Sensitive radioimmunoassay for ouabain characterized by high-performance liquid chromatography.
  
  
  RESULTS
  Serial dilution of urinary immunoreactive ouabain paralleled the standard curve, but not so plasma immunoreactive ouabain. Intravenous administration of 86 nmol (62.5 micrograms) ouabain caused a rapid rise in ouabain immunoreactivity in plasma of healthy volunteers with a maximum of 1.7 nmol/l 8 min after injection and returned to basal levels after 6 h. Ouabain immunoreactivity rose to 36 nmol/l in urine, suggesting that exogenously administered ouabain can be measured reliably in plasma and urine. Analytical reversed-phase high-performance liquid chromatography (isopropanol-propanol biphasic gradient; linear acetonitrile gradient) of sample extracts before assay demonstrated measurable amounts of ouabain-related material only in native urine, but not in plasma. When plasma and urine were spiked with ouabain standard or normal volunteers were injected with ouabain, the assay reliably measured ouabain.
  
  
  CONCLUSIONS
  A substance closely related to ouabain can be detected in urine, but circulates, if at all, in small amounts in human plasma.
authors: Department of Pediatrics, University of Giessen, Germany.
authors: S
authors: S
authors: Worgall
authors: J
authors: J
authors: Hänze
authors: R
authors: R
authors: Wagner
authors: C
authors: C
authors: Peiser
authors: R E
authors: RE
authors: Lang
authors: E
authors: E
authors: Sulyok
authors: W
authors: W
authors: Rascher
mesh_terms: D000328:Adult; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D010042:Ouabain / Q000276:immunology / Q000652:urine*; D011817:Rabbits
chemical_list: D010042:Ouabain