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A radioiodinated linear vasopressin antagonist: A ligand with high affinity and specificity for V 1a receptors
Author(s) -
Schmidt A.,
Audigier S.,
Barberis C.,
Jard S.,
Manning M.,
Kolodziejczyk A.S.,
Sawyer W.H.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80448-c
Subject(s) - vasopressin , antagonist , receptor , vasopressin antagonists , vasopressin receptor , ligand (biochemistry) , chemistry , arginine vasopressin receptor 1b , neuropeptide , medicine , receptor antagonist , oxytocin , endocrinology , biochemistry , stereochemistry , biology
A linear vasopressin antagonist, Phaa‐D‐Tyr(Me)‐Phe‐Gin‐Asn‐Arg‐Pro‐Arg‐Tyr‐NH 2 (Linear AVP Antag) (Phaa = Phenylacetyl), was monoiodinated at the phenyl moiety of the tyrosylamide residue at position 9. This antagonist appeared to be a highly potent anti‐vasopressor peptide with a pA 2 value in vivo of 8.94. It was demonstrated to bind to rat liver membrane preparations with a very high affinity ( K d = 0.06 nM). The affinity for the rat uterus oxytocin receptor was lower ( K i = 2.1 nM), and affinities for the rat kidney‐ and adenohypophysis‐vasopressin receptors were much lower ( K i 47 nM and 92 nM, respectively), resulting in a highly specific vasopressin V 18 receptor ligand. Autoradiographical studies using rat brain slices showed that this ligand is a good tool for studies on vasopressin receptor localization and characterization.