Membrane estrogen receptor engagement activates endothelial nitric oxide synthase via the PI3-kinase-Akt pathway in human endothelial cells

M. Page Haynes, Diviya Sinha, Kerry Strong Russell, Mark Collinge, David Fulton, Manuel Morales-Ruiz, William C. Sessa, Jeffrey R. Bender

Research output: Contribution to journalArticle

455 Scopus citations


17β-Estradiol (E2) is a rapid activator of endothelial nitric oxide synthase (eNOS). The product of this activation event, NO, is a fundamental determinant of cardiovascular homeostasis. We previously demonstrated that E2-stimulated endothelial NO release can occur without an increase in cytosolic Ca2+. Here we demonstrate for the first time, to our knowledge, that E2 rapidly induces phosphorylation and activation of eNOS through the phosphatidylinositol 3 (PI3)-kinase-Akt pathway. E2 treatment (10 ng/mL) of the human endothelial cell line, EA.hy926, resulted in increased NO production, which was abrogated by the PI3-kinase inhibitor, LY294002, and the estrogen receptor antagonist ICI 182,780. E2 stimulated rapid Akt phosphorylation on serine 473. As has been shown for vascular endothelial growth factor, eNOS is an E2-activated Akt substrate, demonstrated by rapid eNOS phosphorylation on serine 1177, a critical residue for eNOS activation and enhanced sensitivity to resting cellular Ca2+ levels. Adenoviral-mediated EA.hy926 transduction confirmed functional involvement of Akt, because a kinase-deficient, dominant-negative Akt abolished E2-stimulated NO release. The membrane-impermeant E2BSA conjugate, shown to bind endothelial cell membrane sites, also induced rapid Akt and consequent eNOS phosphorylation. Thus, engagement of membrane estrogen receptors results in rapid endothelial NO release through a PI3-kinase-Akt-dependent pathway. This explains, in part, the reduced requirement for cytosolic Ca2+ fluxes and describes an important pathway relevant to cardiovascular pathophysiology.

Original languageEnglish (US)
Pages (from-to)677-682
Number of pages6
JournalCirculation research
Issue number8
Publication statusPublished - Oct 13 2000
Externally publishedYes



  • Akt
  • Endothelial nitric oxide synthase
  • Estrogen
  • Membrane receptor

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this