[3H]DUP 753, a highly potent and specific radioligand for the angiotensin II-1 receptor subtype.
[3H]Dup 753, a nonpeptide angiotensin II (AII) receptor antagonist radioligand, was used to characterize a subtype of AII receptors in rat adrenal cortical microsomes. By Scatchard analysis, a single class of DuP 753 binding sites was found with an affinity of 6.4 nM and a Bmax of 1.3 pmol/mg protein. These sites were saturable and readily reversible. Angiotensin (I, II, III) expressed the same affinities and order of potency for these binding sites as those labeled by [3H]AII for the AII-1 sites. The affinities expressed by nonpeptide AII antagonists were commensurate with their inhibitory potencies on AII-1 receptors. PD123177, an AII-2 specific ligand, and other non-AII peptides showed no inhibitory action. These data together with the differential tissue distribution strongly support our conclusion that [3H]DuP 753 is a potent and highly specific radioligand for the AII-1 receptors.
Chiu
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Medical Products Department E.I. du Pont de Nemours & Company, Wilmington, DE 19880-0400.
McCall
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Aldrich
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Timmermans
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D000302:Adrenal Cortex / Q000187:drug effects / Q000378:metabolism*; D000804:Angiotensin II / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D007093:Imidazoles / Q000493:pharmacokinetics*; D007700:Kinetics; D019808:Losartan; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011945:Receptors, Angiotensin / Q000378:metabolism*; D013777:Tetrazoles / Q000493:pharmacokinetics*; D014316:Tritium
D007093:Imidazoles; D011945:Receptors, Angiotensin; D013777:Tetrazoles; D014316:Tritium; D000804:Angiotensin II; D019808:Losartan