Effect of platelet-activating factor on gastrin release from cultured rabbit G-cells.
Gastric infection with Helicobacter pylori is associated with hypergastrinemia. Platelet activating factor (PAF) is produced in H. pylori-infected mucosa. The effects of PAF on gastrin release from cultured antral rabbit G cells were examined. Rabbit antral G-cells were obtained by collagenase-EDTA digestion and enriched by centrifugal elutriation. After 40 hr in culture, gastrin release in response to PAF was assessed. PAF stimulated gastrin release in a dose-dependent manner. A maximal release of 67% above basal was seen with PAF at 100 nM. PAF also enhanced the gastrin release stimulated by forskolin and bombesin. PAF-stimulated gastrin release was abolished by a PAF-receptor antagonist. Gastrin release stimulated by PAF was abolished by chelation of intra- or extracellular calcium or the L-type calcium channel inhibitor verapamil as well as by the protein kinase C inhibitor chelerythrine. Platelet-activating factor may contribute to the hypergastrinemia of H. pylori infection by stimulating gastrin release from G cells. PAF-stimulated gastrin release involves influx of extracellular calcium via L-type channels and activation of protein kinase C.
Department of Gastroenterology, Royal Postgraduate Medical School, Hammersmith Hospital, London.
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Beales
D000818:Animals; D001839:Bombesin / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000502:physiology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D004195:Disease Models, Animal; D019863:Gastrin-Secreting Cells / Q000378:metabolism*; D005755:Gastrins / Q000097:blood / Q000378:metabolism*; D005756:Gastritis / Q000378:metabolism*; D016481:Helicobacter Infections / Q000378:metabolism*; D016480:Helicobacter pylori; D010972:Platelet Activating Factor / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology; D011817:Rabbits
D020746:Calcium Channels, L-Type; D005755:Gastrins; D010972:Platelet Activating Factor; D005576:Colforsin; D011493:Protein Kinase C; D001839:Bombesin