TABLE 2

Affinity of bombesin receptor subtypes for various agonist / antagonists See text for definitions of compound structures for each specific receptor.

Variable Affinitya
BB1 BB2 BB3
nM
Naturally occurring agonist
   GRP 440 18 >10,000
   NMB 4 248 >10,000
   Bombesin 34 4 >10,000
   Litorin 7 6 >10,000
   Ranatensin 13 2 >10,000
   Alytesin 460 62 >10,000
   Phyllolitorin 47 240 >10,000
   Neuromedin C (GRP18–27) 140 20 >10,000
   [Phe13]bombesin 350 0.77 >10,000
Synthetic agonists
   [d-Phe6,β-Ala11,Phe13,Nle14]Bn6–14 0.36 0.99 4.2
   [d-Tyr6,(R)-Apa11,Phe13,Nle14]Bn6–14b 7200 >1900 8.2
   [d-Tyr6,Apa-4Cl11,Phe13,Nle14]Bn6–14b 2400 151 2.8
   Ac-Phe,Trp,Ala,His (tBzl),Nip,Gly,Arg-NH2b 3800 5000 259
   [d-Phe6]Bn6–14 14 2 >10,000
   [d-Phe6,d-Ala11,Leu14]Bn6–14 7600 13 >10,000
Antagonists
   [d-Phe6]Bn6–13 methyl ester 7500 1.1 >10,000
   N-Propionyl-[d-Ala11]GRP20–26 methyl ester 13,660 3.4 >10,000
   Pd 168368 39 1300 1010
   d-Nal,Cys,Tyr,d-Trp,Lys,Val,Cys, Nal-NH2 59 2780 >10,000
   [Tyr4,d-Phe12]Bn6–14 1900 >10,000 >10,000
   [Leu13,ψ13–14,Leu14]Bn6–14 >10,000 430 >10,000
   [d-Phe6,Leu13,Cpa14,ψ13–14]Bn6–14 2700 42 6800
   BW2258U89 >10,000 0.74 >10,000
   [d-Arg1,d-Trp7,9,Leu11]substance P 4,100 11,300 >10,000
   JMV594 >10,000 2.2 >10,000
   JMV641 1500 0.46 >10,000
  • a All data are for rat BB1, mouse BB2, and human BB3 except for data indicated in footnote b. Data are from Coy et al. (1992b), Mantey et al. (1997), Pradhan et al. (1998), Ryan et al. (1998b, 1999), Katsuno et al. (1999), and Tokita et al. (2001b)

  • b Data are from human BB1, BB2, and BB3 (Mantey et al., 2001, 2004, 2006)