Effect of 16,16-dimethyl prostaglandin E2 and ethanol on the constituents of gastric mucus.
The effect of ethanol, 16,16-dimethyl prostaglandin E2 (DMPGE2), and ethanol after DMPGE2 pretreatment on the solubilization of protein, glycoprotein, and glycolipid constituents of gastric mucus was investigated. The Lucite chamber stomach-flap preparation was used in dogs whose basal H+ secretion was inhibited by intravenous cimetidine. Graded concentrations (5-80%) of ethanol produced a dose-dependent decrease in potential difference (PD) which was accompanied by an increase in the content of proteins, glycoproteins, and glycolipids of the instillates. This effect was most pronounced at 40% ethanol. Exposure of gastric mucosa to DMPGE2 at 0.01 microgram/ml had no effect on the transmucosal PD, and the content of investigated components in the instillates increased only slightly over the saline control levels. DMPGE2 at 0.1 microgram/ml, although it did not induce an evident fall of PD, evoked a moderate increase in glycoprotein and glycolipid liberation. Higher doses (above 1.0 microgram/ml) of DMPGE2 were associated with the fall of PD and the increased solubilization of proteins, glycoproteins, and glycolipids. Pretreatment of the mucosa with DMPGE2 in a dose of 1.0 microgram/ml diminished the liberation of the investigated components from the gastric mucosa by 5 and 10% ethanol, but did not prevent the changes evoked by higher concentrations (20-80%) of ethanol. These data indicate that DMPGE2 applied topically protects in part the gastric mucosa against the ethanol-induced solubilization of mucus constituents.
D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology*; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism*; D006023:Glycoproteins / Q000032:analysis; D007700:Kinetics; D008297:Male; D008358:Mannose / Q000032:analysis; D009093:Mucus / Q000378:metabolism*; D011459:Prostaglandins E, Synthetic / Q000494:pharmacology*; D011506:Proteins / Q000032:analysis
D002241:Carbohydrates; D006023:Glycoproteins; D011459:Prostaglandins E, Synthetic; D011506:Proteins; D000431:Ethanol; D015064:16,16-Dimethylprostaglandin E2; D008358:Mannose