V1-like [Arg8]vasopressin binding sites occur in rat hepatocyte nuclei.
Arginine vasopressin binding site characterisation was performed on purified nuclei and plasma membranes from livers of Sprague-Dawley rats. [125I][d(CH2)5,Sarc7,Arg8]vasopressin, a selective V1 vasopressin receptor antagonist radioligand, bound to the nuclei in a protein concentration and time dependent manner. Scatchard analysis of nuclear binding sites revealed a single binding site with maximal binding site density (Bmax) of 115 +/- 13 fmol/mg protein and affinity (KD) of 5.2 +/- 0.7 nM. Plasma membrane binding demonstrated a Bmax of 529 +/- 25 fmol/mg protein and KD of 1.9 +/- 0.1 nM. The displacement profile for nuclear binding sites using vasopressin analogues was similar to that for plasma membrane binding sites and was typical of a V1 vasopressin receptor type. There was no evidence of V2-like vasopressin receptor binding using [3H]des-Gly-NH9(2)[d(CH2)5,D-Ile2,Ile4,Arg8]vasopressi n, a selective V2 vasopressin receptor radioligand, in the nuclear or membrane fractions. These results suggest the existence of nuclear V1-like vasopressin binding sites.
Phillips
P A
PA
Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Australia.
Hutchins
A M
AM
Burrell
L M
LM
Risvanis
J
J
Johnston
C I
CI
D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D005260:Female; D066298:In Vitro Techniques; D008024:Ligands; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D014176:Protein Biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017483:Receptors, Vasopressin / Q000187:drug effects / Q000378:metabolism*; D014667:Vasopressins / Q000493:pharmacokinetics
D008024:Ligands; D017483:Receptors, Vasopressin; C070737:argipressin, beta mercapto(beta,beta)-cyclopentamethylenepropionic acid(1)-Ile(2,4)-Ala-NH2(9)-; C090704:vasopressin, beta mercapto-beta,beta-cyclopentamethylenepropionic acid-Sarc(7)-Arg(8)-; D014667:Vasopressins; D001127:Arginine Vasopressin; D004247:DNA