Evidence on the presence of secretin cells in the gastric antral and oxyntic mucosa.

Secretin is released from upper small intestinal mucosa to drive pancreatic secretion of fluid and bicarbonate and inhibit gastric acid secretion. Recently, we found that, in isolated, vascularly perfused rat stomach model, the inhibition of acid secretion by pituitary adenylate cyclase activating polypeptide (PACAP) was mediated in part via local release of secretin. However, the presence of secretin-producing cells and mRNA in gastric mucosa, particularly in oxyntic mucosa, has not been established. The present study was carried out to establish the presence of secretin cells by immunohistochemical and mRNA by biochemical methods in gastric mucosa. Secretin cells were identified in antral mucosa (27.8 +/- 2.0 cells/mm(2)) and corpus (4.7 +/- 0.5 cells/mm(2)). They were distinguishable, through double immunostaining, from gastrin and somatostatin cells in the antrum and from somatostatin cells in the corpus. The results of reverse transcription (RT)-PCR and Southern blot indicated that a secretin gene transcript of 454 bp was present in the mRNA extracts of both antral and corpus mucosae. The results indicated that secretin mRNA is present in gastric mucosa. In conclusion, secretin-producing cells and mRNA are present in gastric mucosa and the locally released secretin may exert a paracrine effect to inhibit acid secretion.