Pharmacological characterization of VIP receptors in human lung membranes.
The ability of VIP, PHI, secretin, helodermin, and seven N-terminally D-amino monosubstituted VIP and PHI analogs to occupy (125I)iodo-VIP labeled receptors and to activate adenylate cyclase was tested on human lung membranes purified by the method of Schachter et al. Best fitted Kd, Kact and % of max. values suggested the coexistence, in near equal proportions, of two classes of VIP-preferring binding sites coupled to adenylate cyclase that showed similar decreasing affinity for: VIP greater than (D-Ala4)-VIP greater than (D-Asp3)-VIP = (D-Ser2)-VIP greater than (D-His1)-VIP greater than PHI greater than (D-Phe2)-VIP greater than (D-Phe4)-VIP. (D-Arg2)-VIP was a non-selective agonist. A third receptor type, coupled to adenylate cyclase and showing high affinity for secretin and helodermin but not for VIP, was also detected.
Robberecht
P
P
Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium.
Waelbroeck
M
M
de Neef
P
P
Camus
J C
JC
Coy
D H
DH
Christophe
J
J
D000328:Adult; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008875:Middle Aged; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide