Bile salts stimulate mucous glycoprotein secretion from cultured rabbit gastric mucosal cells

Resistance of gastric mucosa to damage is increased after exposure to mild irritants such as bile salts (adaptive cytoprotection). Mucus secretion also contributes to gastric cytoprotection. We investigated whether bile salts stimulate mucous glycoprotein secretion from cultured rabbit gastric mucosal cells. Because prostaglandins (PGs) stimulate mucus secretion, we assessed the role of endogenous PG release in bile salt-stimulated mucus secretion. Because Ca2+ plays a role in PGE2 release, the role of extracellular Ca2+ on PGE2 release and mucus secretion by bile salts was also studied. Rabbit gastric mucosal cells were prepared with collagenase and ethyl-enediaminetetraacetic acid. These cells were cultured as described previously. Cytotoxicity of bile salts was quantified by measuring chromium 51 release from prelabeled cells. PGE2 was measured by radioimmunoassay. Mucous glycoprotein secretion was assessed by tritiated glucosamine release assay. Deoxycholate (DC) and glycodeoxycholate (GDC) stimulated tritiated glucosamine release in doses that were not cytotoxic to the cultured cells. DC stimulated PGE2 release that was blocked by deprivation of extracellular Ca2+. GDC did not stimulate PGE2 release. Neither DC-stimulated nor GDC-stimulated mucus secretion was affected by indomethacin. Deprivation of extracellular Ca2+ did not affect DC-stimulated or GDC-stimulated mucus secretion. Bile salts stimulated mucous glycoprotein secretion from cultured rabbit gastric mucosal cells. This effect occurred independently of changes in endogenous PGE2 or extracellular Ca2+ concentrations.