Identification of atypical (non-AT1, non-AT2) angiotensin binding sites with high affinity for angiotensin I on IEC-18 rat intestinal epithelial cells.
Specific high-affinity (Kd = 3.4 nM) binding sites for 125I-labelled angiotensin I ([125I]Ang I) were identified on an epithelial cell line (IEC-18) derived from the rat small intestine. The sites, which also have high affinity for Ang II, are insensitive to both AT1- and AT2-specific angiotensin receptor antagonists. The rank order of potency with which various angiotensin peptides inhibited [125I]Ang I binding to the cells (Ang I > or = Ang II > Ang(1-7) > [Sar1,Ile8]-Ang II > Ang(3-8) > Ang III) also distinguishes these sites from AT1 and AT2 angiotensin receptors.
Smith
R D
RD
Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, UK.
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000803:Angiotensin I / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D000805:Angiotensin III / Q000494:pharmacology; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001713:Biphenyl Compounds / Q000494:pharmacology; D002460:Cell Line; D004848:Epithelium / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism; D019808:Losartan; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011945:Receptors, Angiotensin / Q000378:metabolism*; D013777:Tetrazoles / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D001713:Biphenyl Compounds; D007093:Imidazoles; D009842:Oligopeptides; D010446:Peptide Fragments; D011725:Pyridines; D011945:Receptors, Angiotensin; D013777:Tetrazoles; D000804:Angiotensin II; D000805:Angiotensin III; C060894:CGP 42112A; C073402:PD 123319; D000803:Angiotensin I; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; C118790:angiotensin I (1-7); D019808:Losartan