Endogenous prostaglandins are physiological regulators of endocrine cells in the gastroduodenal mucosa of the rat.
OBJECTIVE
To investigate whether endogenous prostaglandins participate in the regulation of the gastrointestinal endocrine cell system.


METHODS
Sprague-Dawley rats were treated with 1 mg/kg indomethacin subcutaneously or indomethacin subcutaneously and 500 microg/kg oral prostaglandin E2 or solvents for 2 months. Endocrine cells were visualized by using immunohistochemistry and by the Sevier-Munger silver stain on specimens from the gastroduodenal mucosa, and their total volume was estimated, using standard stereological methods. Plasma and gastrointestinal tissue concentrations of regulatory peptides were analyzed by radioimmunoassay.


RESULTS
Fundic mucosa. The total volume of cells stained with the Sevier-Munger silver stain (enterochromaffin-like) was increased by indomethacin, but reduced by the administration of prostaglandin E2 (P < 0.05 vs. indomethacin). Indomethacin increased the total volume of somatostatin-immunoreactive. Similarly, rats given indomethacin and prostaglandin E2 had higher values than controls. Indomethacin increased the tissue concentration of somatostatin in the gastric fundus whereas prostaglandin E2 prevented such changes (P < 0.05 vs. indomethacin). Antral mucosa. The total volume of serotonin-immunoreactive cells was reduced by indomethacin, but increased by prostaglandin E2 (P < 0.05 vs. controls and indomethacin, respectively). Duodenal mucosa. The total volume of somatostatin-immunoreactive cells was reduced in the rats given indomethacin and prostaglandin E2 (P < 0.05 vs. controls and indomethacin). Indomethacin reduced and simultaneous administration of prostaglandin E2 increased the total volume of CCK-immunoreactive cells (P < 0.05 vs. controls and indomethacin). Indomethacin reduced the total volume of serotonin-immunoreactive cells whereas the simultaneous administration of PGE2 comparatively increased their total volumes (P < 0.05 vs. indomethacin), although they were still lower than the control values. The total volume of GIP-immunoreactive cells was slightly increased in the rats given both indomethacin and indomethacin + prostaglandin E2. The tissue concentration of somatostatin in the duodenum was reduced in rats given indometacin and prostaglandin E2 (P < 0.05 vs. controls and indomethacin).


CONCLUSIONS
Endogenous prostaglandins, particularly prostaglandin E2, regulate CCK-, enterochromaffin-like-, somatostatin-, GIP- and enterochromaffin cells in the gastroduodenal mucosa of the rat.
Kapraali
M
M
Division of Internal Medicine, Danderyd Hospital, Karolinska Institute, Sweden.
Johansson
O
O
Uribe
A
A
D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D004759:Enterochromaffin Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D005748:Gastric Fundus / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D007150:Immunohistochemistry; D007213:Indomethacin / Q000494:pharmacology; D007279:Injections, Subcutaneous; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D011453:Prostaglandins / Q000502:physiology*; D011706:Pyloric Antrum / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011453:Prostaglandins; D015232:Dinoprostone; D007213:Indomethacin