On the metabolism of prostaglandins by human gastric fundus mucosa.
1. Specific radioimmunoassays for the prostaglandins E2, F2alpha and A2 and the metabolites 13,14-dihydro-15-keto-prostaglandin E2, 15-keto-prostaglandin F2alpha and 13,14-dihydro-15-keto-prostaglandin F2alpha were used to study the metabolism of prostaglandins by gastroscopically obtained small biopsy specimens of human gastric fundus mucosa. 2. Three prostaglandin-metabolizing enzymes were found in the 100 000 X g supernatant of human gastric fundus mucosa, 15-hydroxy-prostaglandin-dehydrogenase, delta13-reductase and delta9-reductase. The specific activity was highest for 15-hydroxy-prostaglandin-dehydrogenase and lowest for delta9-reductase. 3. Formation of prostaglandin A2 (or B2) was not observed under the same conditions. 4. None of the three enzyme activities detected in the 100 000 X g supernatant was found in the 10 000 X g and 100 000 X g pellets of human gastric fundus mucosa. 5. The results indicate that high speed supernatant derived from human gastric mucosa can rapidly metabolize prostaglandin E2 and prostaglandin F2alpha to the 15-keto and 13,14-dihydro-15-keto-derivatives. Furthermore, prostaglandin E2 can be converted to prostaglandin F2alpha, the biological activity of which, on gastric functions, differs from that of prostaglandin E2.
D000328:Adult; D000368:Aged; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011454:Prostaglandins A / Q000378:metabolism*; D011458:Prostaglandins E / Q000378:metabolism*; D011460:Prostaglandins F / Q000378:metabolism*
D011454:Prostaglandins A; D011458:Prostaglandins E; D011460:Prostaglandins F