|Budget Amount *help
¥2,400,000 (Direct Cost : ¥2,400,000)
Fiscal Year 1992 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1991 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1990 : ¥700,000 (Direct Cost : ¥700,000)
Mucin plays a principal role in protecting the gastric mucosa against injury. We investigated the effect of acid secretagogues and epidermal growth factor (EGF) on mucin synthesis using a primary gastric mucous cell monolayer culture system of guinea pig. Significant increases in mucin synthesis were observed in response to the secretagogues pentagastrin, carbachol, and EGF, but not to histamine. After pretreatment with indomethacin, pentagastrin and EGF significantly increased mucin synthesis, but carbachol did not. Prostaglandin E2 release into the culture medium was significantly increased by carbachol and EGF, but there was no change after application of pentagastrin. These findings suggest that pentagastrin, carbachol, and EGF may act directly on mucous cells, and that part of the mucin synthesis-promoting action of carbachol is mediated by prostaglandins. However, the stimulation of mucin synthesis by pentagastrin and EGF occurs through a prostaglandin-independent mechanism. There were no changes in intracellular cAMP concentration after the addition of these acid secretagogues and EGF. However, calcium ionophore (A23187) produced an increase in mucin synthesis, suggesting a Ca2+ involvement in muchi synthesis. No differences were found in the sugar side structures of newly synthesized mucin glycoprotein as a result of exposure to acid secretagogues by histochemical or biochemical methods using lectins.