Prostaglandin E2 in basal gastric secretion and during stimulation of muscarinic receptors in man. Measurements with gas chromatography--mass spectrometry.
The physiological importance of prostaglandin E2 (PGE2) biosynthesis in the gastric mucosa is unknown. A role of endogenous prostaglandins in protecting the gastrointestinal epithelia has been suggested, but the evidence is insufficient and rarely supported by concomitant measurement of PG production. Amounts of PGE2 in luminal gastric contents which can be sampled atraumatically may reflect PGE2 synthesis in the gastric mucosa in vivo. To confirm earlier reported measurements made with radioimmunoassay we have measured by gas chromatography - mass spectrometry (GC-MS) PGE2 in gastric juice of five healthy men under basal conditions and during stimulation of muscarinic receptors with iv. bethanechol which in dog is reported to enhance PGE2 output. PGE2 was detected in all basal samples. The output was in median 32.1 pmol/15 min (range 17.0-105.4, 1 pmol = 0.352 ng), which is similar to results from earlier studies. Bethanechol infusion (60 micrograms . kg-1 . h-1) did not affect PGE2 outputs systematically in spite of a significant increase in outputs of acid and chlorides. Stimulation of muscarinic receptors does not seem to influence PGE2 synthesis in gastric mucosa in vivo. Alternatively changes in PGE2 synthesis may be masked by rapid chemical or enzymatical degradation or reabsorption of PGE2. Studies are under way to explore those phenomena.
D000328:Adult; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology*; D015232:Dinoprostone; D008401:Gas Chromatography-Mass Spectrometry; D005750:Gastric Juice / Q000032:analysis; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011458:Prostaglandins E / Q000032:analysis / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000187:drug effects*
D001626:Bethanechol Compounds; D011458:Prostaglandins E; D011976:Receptors, Muscarinic; D018723:Bethanechol; D015232:Dinoprostone