Lipopolysaccharide-induced inhibition of gastric acid and pepsin secretion in rats.

We used male Wistar rats to determine the effects of lipopolysaccharide (LPS) on gastric secretion. After pylorus ligation, 24-h fasted rats received i.p. injections of different doses of LPS dissolved in sterile saline. The amounts of gastric acid and pepsin secreted were determined 2, 4 or 8 h after injection. Small doses of LPS (10-1000 ng/rat) significantly inhibited the release of both gastric secretants as compared with control animals, and this inhibitory effect of LPS on gastric secretion was dose-related. The gastric antisecretory effect of LPS was still evident 8 h after injection, indicating that this action of LPS was long-lasting. These results suggest that LPS might be involved in the regulation of gastric secretion under certain pathophysiological conditions such as acute bacterial infections.