Antagonism by GRP(18-27) and substance P analogues on insulin release stimulated by GRP(18-27).
The antagonistic effects of [D-Phe25]gastrin-releasing peptide (GRP)(18-27) and [D-Arg1,D-Pro2,D-Trp7,9,Leu11]substance P (SP) on the stimulation of insulin release by GRP(18-27) from isolated canine pancreas were compared with that of [Ala23]GRP(18-27). The stimulation of insulin release by 1 nM GRP(18-27) was reduced to 24.1% and 15.4% by the prior infusion of 1 microM of [D-Arg1,D-Pro2,D-Trp7,9,Leu11]SP and 10 microM of [D-Phe25]GRP(18-27), respectively. Glucagon release by GRP(18-27) was not affected by these peptides using the above concentrations. The results indicate that these peptides are antagonists of bombesin-like peptide receptors on pancreatic B-cells, although the inhibitory activities are lower than that of [Ala23]GRP(18-27).
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki-ken, Japan.
H
H
Mukai
K
K
Kawai
S
S
Suzuki
K
K
Yamashita
E
E
Munekata
D000595:Amino Acid Sequence; D000818:Animals; D001839:Bombesin / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D004285:Dogs; D019886:Gastrin-Releasing Peptide; D005934:Glucagon / Q000378:metabolism; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D011994:Recombinant Proteins; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology
D007328:Insulin; D010446:Peptide Fragments; D010455:Peptides; D011994:Recombinant Proteins; C064112:gastrin releasing peptide (18-27), Phe(25)-; D013373:Substance P; D019886:Gastrin-Releasing Peptide; C040794:neuromedin C; C050702:substance P, Arg(1)-Pro(2)-Trp(7,9)-Leu(11)-; D005934:Glucagon; D001839:Bombesin