High-affinity receptors for bombesin-like peptides in normal guinea pig lung membranes.
The binding of the radiolabelled bombesin analogue [125I-Tyr4]bombesin to guinea-pig lung membranes was investigated. Binding of [125I-Tyr4]bombesin was specific, saturable, reversible and linearly related to the protein concentration. Scatchard analysis of equilibrium binding data at 25 degrees C indicated the presence of a single class of non-interacting binding sites for bombesin (Bmax = 7.7 fmol/mg protein). The value of the equilibrium dissociation constant (KD = 90 pM) agrees with a high-affinity binding site. Bombesin and structurally related peptides such as [Tyr4]bombesin, neuromedin B and neuromedin C inhibited the binding of [125I-Tyr4]bombesin in an order of potencies as follows: [Tyr4]bombesin greater than bombesin greater than or equal to neuromedin C much greater than neuromedin B. These results indicate that guinea-pig lung membranes possess a single class of bombesin receptors with a high affinity for bombesin and a lower one for neuromedin B.
Lach
E
E
Laboratoire de Neuroimmunopharmacologie, Université Louis Pasteur-Strasbourg I, Faculté de Pharmacie, Illkirch, France.
Trifilieff
A
A
Landry
Y
Y
Gies
J P
JP
D000818:Animals; D001665:Binding Sites; D001839:Bombesin / Q000378:metabolism*; D006168:Guinea Pigs; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008297:Male; D015287:Neurokinin B / Q000031:analogs & derivatives / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D010455:Peptides; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter; D014443:Tyrosine; D015287:Neurokinin B; C038393:neuromedin B; D001839:Bombesin