To understand the mechanism by which prostaglandins (PGs) preserve gastric mucosal integrity, we established a primary cultured monolayer of guinea pig gastric mucous cells, and by using this culture system, we studied whether endogenously released PGE
2 could influence the proliferation of the mucous cells. By the histochemical and morphological analysis at 24h of the culture periods, the cells were recognized to contain PAS-positive mucous granules with only 3% of them being parietal cells. Although the cells which were simultaneously labeled with [
3H] arachidonic acid in 0.5% serum-containing medium synthesized and released radiolabeled PGE
2, PGI
2 and PGA
2, the release of PGE
2 was more markedly observed and was partially dependent upon arachidonic acid added to the ulture medium. By radioimmunoassay of the culture media, the mucous cells were found to release PGE
2 in a time-dependent manner in response to 10% serum.
Pretreatment of the cells with 10
-4M indomethacin not only inhibited PGE
2 release but also inhibited increase in cell number. However, the addition of PGE
2 dose-dependently restored the indomethacin-induced inhibition of cell growth with the maximal increase almost to the control level at 10
-6M PGE
2. These results suggest that PGE
2 endogenously released from the cells may exert a proliferative effect on gastric mucous cells.
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