Endogenous prostaglandins are physiological regulators of endocrine cells in the gastroduodenal mucosa of the rat

Background/Aim: To investigate whether endogenous prostaglandins participat e 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 mu g/kg oral prostaglandin E-2 or so lvents for 2 months. Endocrine cells were visualized by using immunohistoch emistry and by the Sevier-Munger silver stain on specimens from the gastrod uodenal mucosa, and their total volume was estimated, using standard stereo logical methods. Plasma and gastrointestinal tissue concentrations of regul atory peptides were analyzed by radioimmunoassay. Results: Fundic mucosa. T he total volume of cells stained with the Sevier-Munger silver stain (enter ochromaffin-like) was increased by indomethacin, but reduced by the adminis tration of prostaglandin E-2 (P < 0.05 vs. indomethacin). Indomethacin incr eased the total volume of somatostatin-immunoreactive. Similarly, rats give n indomethacin and prostaglandin E-2 had higher values than controls. Indom ethacin increased the tissue concentration of somatostatin in the gastric f undus whereas prostaglandin E-2 prevented such changes (P < 0.05 vs, indome thacin). Antral mucosa. The total volume of serotonin-immunoreactive cells was reduced by indomethacin, but increased by prostaglandin E-2 (P < 0.05 v s. controls and indomethacin, respectively). Duodenal mucosa. The total vol ume of somatostatin-immunoreactive cells was reduced in the rats given indo methacin and prostaglandin E-2 (P < 0.05 vs. controls and indomethacin). In domethacin reduced and simultaneous administration of prostaglandin E-2 inc reased the total volume of CCK-immunoreactive cells (P < 0.05 vs. controls and indomethacin). Indomethacin reduced the total volume of serotonin-immun oreactive cells whereas the simultaneous administration of PGE(2) comparati vely increased their total volumes (P < 0.05 us. indomethacin), although th ey were still lower than the control values. The total volume of GIP-immuno reactive cells was slightly increased in the rats given both indomethacin a nd indomethacin + prostaglandin E-2. The tissue concentration of somatostat in in the duodenum was reduced in rats given indometacin and prostaglandin E-2 (P < 0.05 vs. controls and indomethacin). Conclusion: Endogenous prosta glandins, particularly prostaglandin E-2, regulate CCK-, enterochromaffin-l ike-, somatostatin-, GIP- and enterochromaffin cells in the gastroduodenal mucosa of the rat. (C) 1999 Elsevier Science BN. All rights reserved.