The effects of acid secretagogues on protective agents of gastric cells from adult rabbits in vitro.
Endogenous prostaglandin and mucus have been recognized as important protective factors in the gastric mucosa. However, the regulatory mechanisms of these agents have not been well studied. The aim of the present study was to investigate the effects of acid secretagogues on cyclic adenosine monophosphate (cAMP) formation, prostaglandin E2 (PGE2) production, and mucus secretion by isolated parietal cells and culture mucous cells from adult rabbits. Rabbit parietal cells were enriched by nonlinear Percoll gradients after the isolation of rabbit gastric mucosal cells with collagenase and ethylenediaminetetraacetic acid (EDTA). Rabbit gastric mucous cells were cultured in 10% fetal bovine serum added to Ham's F12 medium. As gastric acid secretagogues, histamine, carbachol, gastrin, and 2-chloroadenosine were tested. To evaluate the effects of the second messengers of cellular signal transduction on protective agents, A23187, which is a calcium ionophore, and cAMP were used. PGE2 and cAMP were measured by radioimmunoassay. The release of [3H]glucosamine from prelabeled cells was used as an indicator of mucus secretion. Histamine, carbachol, gastrin, and 2-chloroadenosine did not modulate PGE2 production by parietal cells. Exogenously administered cAMP did not affect PGE2 production by parietal cells, whereas it was significantly increased by A23187. 2-Chloroadenosine but not histamine or carbachol significantly increased cAMP formation by mucous cells. Histamine, carbachol, and gastrin did not have significant effects on PGE2 production by mucous cells. 2-Chloroadenosine, which increased cAMP, also did not modulate PGE2 production. A23187 but not cAMP increased PGE2 production by mucous cells. None of the acid secretagogues used in the present study modulated mucus secretion. A23187 but not cAMP significantly increased mucus secretion by cultured mucus cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Ota
S
S
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Hata
Y
Y
Hiraishi
H
H
Mutoh
H
H
Terano
A
A
Sugimoto
T
T
D015762:2-Chloroadenosine / Q000494:pharmacology*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005755:Gastrins / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009093:Mucus / Q000378:metabolism*; D010295:Parietal Cells, Gastric / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011458:Prostaglandins E / Q000378:metabolism*; D011817:Rabbits
D005755:Gastrins; D011458:Prostaglandins E; D015762:2-Chloroadenosine; D000001:Calcimycin; D006632:Histamine; D002217:Carbachol; D000242:Cyclic AMP