[Endothelin receptors and endothelin-1 immunoreactivity in the human lung].
We investigated in human lung preparations the characteristics of endothelin-1 (ET-1) binding and the amount of ET-1-like immunoreactivity. Saturation experiments revealed the presence of a large number of high affinity specific ET-1 binding sites with a dissociation constant (Kd) of 1.35 nM and a binding capacity (Bmax) of 9.74 pmol/mg of protein. The binding was time- and temperature-dependent and dissociated by only 10% by the addition of 1 microM unlabeled ET-1. In competition experiments, [125I]ET-1 binding was totally inhibited by unlabeled ET-1 and ET-2 with inhibition constant (Ki) values of 0.20 and 0.21 nM respectively, and 80% inhibited by ET-3 with Ki value of 0.50 nM. The binding was not affected by 1 microM structurally unrelated compounds. Moreover a high level of ET-1-like immunoreactivity (2.3 pg/mg wet weight) was found in human lung by using a specific radioimmunoassay of ET-1 after extraction. HPLC analysis revealed the presence of both ET-1 and Big-ET. These results suggest that the lung may be an important target organ for ET-1 action and/or metabolism in human.
Gillard
V
V
Institut Henri-Beaufour, Les Ulis.
Roubert
P
P
Viossat
I
I
Loquet
I
I
Chapelat
M
M
Brink
C
C
Chabrier
P E
PE
Braquet
P
P
D001665:Binding Sites / Q000276:immunology; D046508:Culture Techniques; D016232:Endothelins / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000276:immunology*; D011863:Radioimmunoassay; D011956:Receptors, Cell Surface / Q000276:immunology*; D017466:Receptors, Endothelin
D016232:Endothelins; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin
Récepteurs de l'endothéline et immunoréactivité de l'endothéline-1 au niveau des poumons humains.