Inhibition of bombesin-stimulated gastrin release from isolated canine G cells by bombesin antagonists.
This study investigated the effects of two putative bombesin antagonists, [D-Arg1,D-Pro2,D-Trp7,9,Leu11]substance P and [Leu13-psi-CH2NH-Leu14]bombesin, on bombesin-stimulated gastrin release from isolated canine G cells following short-term culture. Canine antral tissue was dispersed by sequential collagenase and EDTA treatment, and counterflow elutriation was used to enrich for G cells. Plates were seeded with 2 x 10(6) cells/mL in each well and cultured for 2 days prior to testing. Gastrin-containing and somatostatin-containing cells were identified by immunocytochemistry using the biotin-avidin-peroxidase method and accounted for 8.5 and 1%, respectively, of adhered cells. Basal gastrin secretion was 1.91 +/- 0.48% of total cell content. After a 2-h incubation period, bombesin (0.01-100 pM) stimulated gastrin release in a concentration-dependent fashion. The substance P analog, at a concentration of 1 microM, modestly inhibited bombesin-stimulated gastrin release from canine G cells. This analog also produced weak stimulation of basal gastrin release. In contrast, the bombesin analog, at a concentration of 1 microM, did not affect basal gastrin secretion. The bombesin analog completely blocked bombesin-stimulated gastrin release from 0.01 to 1 pM and produced greater than 50% inhibition at higher doses. The ability of the bombesin analog to directly inhibit bombesin-stimulated gastrin release from cultured canine G cells underscores its usefulness in studies involving the role of bombesin and its mammalian counterpart, gastrin-releasing peptide, in the control of gastrin cell function.
Campos
R V
RV
Department of Physiology, University of British Columbia, Vancouver, Canada.
Buchan
A M
AM
Pederson
R A
RA
McIntosh
C H
CH
Coy
D H
DH
D000818:Animals; D001839:Bombesin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004285:Dogs; D005753:Gastric Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019886:Gastrin-Releasing Peptide; D005755:Gastrins / Q000378:metabolism*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D010455:Peptides / Q000378:metabolism*; D011863:Radioimmunoassay; D011994:Recombinant Proteins; D013004:Somatostatin / Q000276:immunology / Q000378:metabolism; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology
D005755:Gastrins; D010455:Peptides; D011994:Recombinant Proteins; C057644:bombesin, Leu(13)-psi-CH2NH-Leu(14)-; D013373:Substance P; D013004:Somatostatin; D019886:Gastrin-Releasing Peptide; C050702:substance P, Arg(1)-Pro(2)-Trp(7,9)-Leu(11)-; D001839:Bombesin