Modifications induced by plasma of gestational hypertensive women on the Na+/K+-ATPase obtained from human placenta

N. Cester, R. A. Rabini, A. L. Tranquilli, G. Lucarelli, E. Salvolini, R. Staffolani, E. Amler, G. Zolese, L. Mazzanti

Research output: Contribution to journalArticlepeer-review


In order to investigate the molecular mechanisms of the inhibition of Na+/K+-ATPase in Gestational Hypertension (GH), we incubated Na+K+-ATPase purified from human placenta of 6 healthy normotensive women with plasma from 6 GH women and 6 healthy controls. We determined the enzyme activity by the method of Esman, and the anthroyl-ouabain-binding capacity, dissociation constant (K(d)) and average lifetime values (τ) by the static and dynamic fluorescence of anthroyl-ouabain. The lipid annulus of the enzyme was studied by static and dynamic fluorescence of 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH). The addition of total and protein-free GH plasma to normal Na+/K+-ATPase significantly inhibited the enzymatic activity even at the lowest concentration studied (1:100), as well as the ouabain-binding capacity, K(d) and τ. GH plasma significantly decreased the fluorescence polarization and lifetime values of TMA-DPH. These observations indicate that the inhibition caused by GH plasma on Na+/K+-ATPase might be due to a reduction of the number of active molecules or a modification of the ouabain-binding site suggesting the existence of digitalis-like factor. A link between the modification of the lipid moiety of the enzyme and the Na+/K+-ATPase inhibition might be hypothesized.

Original languageEnglish
Pages (from-to)125-129
Number of pages5
JournalMolecular and Cellular Biochemistry
Issue number1-2
Publication statusPublished - 1997


  • Activity
  • Fluorescence
  • Gestational hypertension
  • Ouabain
  • Plasma

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


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