title: Release of endogenous prostaglandins by mild hyperosmotic saline inhibits tetragastrin-stimulated gastric acid secretion in rats.
abstract: Filling of the gastric lumen of rats with 1.0 M NaCl solution (5 ml) for 10 min under urethane anesthesia caused an increase in the gastric fluid concentrations of prostaglandin (PG) E2, 13,14-dihydro-15-keto-PGE2 and 6-keto-PGF1 alpha as determined by radioimmunoassay. PGE2 was the major PG generated. The levels of PGE2 in the gastric fluid were increased dose-dependently after filling the lumen with 0.3, 0.5, 0.7 or 1.0 M NaCl solutions. The pH of the gastric fluid increased similarly after 0.5 to 1.0 M NaCl solutions. Indomethacin (10 mg/kg, i.p.) suppressed the PGE2 increase caused by 1.0 M NaCl solution, but did not prevent the increase of the pH of the gastric fluid induced by intragastric 1.0 M NaCl. Infusion of tetragastrin (62.5 micrograms/kg/hr, i.v., for 10 min) caused a marked increase of acid secretion without modifying intragastric concentration of PGE2. The acid secretion due to tetragastrin was completely inhibited after intragastric administration of 1.0 M NaCl solution, while indomethacin restored the tetragastrin-induced acid secretion, with prevention of a rise of intragastric PGE2 levels. These observations suggest that 1.0 M NaCl solutions suppress basal intragastric acid through a mechanism which is independent of prostaglandins. In contrast, the suppression of tetragastrin-induced acid secretion by intragastric 1.0 M NaCl solution appears to be mediated through a release of prostaglandins.
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Harada
authors.forename: A
authors.initials: A
authors.lastname: Ueno
authors.forename: M
authors.initials: M
authors.lastname: Katori
authors.forename: H
authors.initials: H
authors.lastname: Okabe
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism; D000818:Animals; D015232:Dinoprostone / Q000031:analogs & derivatives; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D005755:Gastrins / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D011453:Prostaglandins / Q000378:metabolism*; D011458:Prostaglandins E / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013758:Tetragastrin / Q000494:pharmacology*
chemical_list: D005755:Gastrins; D011453:Prostaglandins; D011458:Prostaglandins E; D012462:Saline Solution, Hypertonic; D013758:Tetragastrin; C025087:15-keto-13,14-dihydroprostaglandin E2; D012965:Sodium Chloride; D015121:6-Ketoprostaglandin F1 alpha; D015232:Dinoprostone; D007213:Indomethacin