A common low-affinity binding site for primary prostanoids on bovine aortic endothelial cells

Julia Mazar-Feldman, Gilad Rimon

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


[3H]PGE2 and [3H]PGF(2α) were shown to bind with similar binding capacity and dissociation constants to bovine aorta endothelial cells. The similarity in the binding parameters suggests that both agonists may bind to the same binding site. Displacement of [3H]PGE2 performed with PGE2, PGF(2α) or U-46619, a thromboxane agonist, shows that all three prostanoids displaced the bound [3H]PGE2 with comparable potency (IC50 = 10-7 M). These results indicated that the three different prostanoids, which serve as specific agonists to different prostanoid receptors, also compete for the same binding site in bovine endothelial cells with similar affinity. Comparison of the displacement of [3H]PGE2 or [3H]PGF(2α) by a number of prostaglandin agonists and antagonists further supports the notion that the natural prostanoids bind with similar affinities to the same binding site. Thus, sulprostone, an EP1/EP3 agonist, displaced bound [3H]PGE2 and [3H]PGF(2α) with IC50 of about 10-7 M. On the other hand, thromboxane antagonists (BAY u-3405 and GR-32191B), EP1 specific antagonist (SC-19220) EP1/DP antagonist (AH-6809) and iloprost, a stable prostacyclin agonist, failed to displace bound [3H]PGF(2α) or [3H]PGF(2α) at a concentration range of 10-9-10-6 M. Gradual increase of sodium fluoride (NaF), a general activator of G binding proteins, or incubation of permeabilized cells with GTPγS resulted in a decrease in [3H]PGE2 binding, suggesting that the binding site represents a low-affinity common prostanoid receptor which, similar to other prostanoid receptors, is probably coupled with G binding proteins.

Original languageEnglish
Pages (from-to)497-501
Number of pages5
JournalCellular Signalling
Issue number7
StatePublished - 1 Nov 1996


  • Binding
  • Bovine aorta
  • Endothelial cell
  • GTPγS
  • Prostanoid receptor
  • Sodium fluoride

ASJC Scopus subject areas

  • Cell Biology


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