Release of prostaglandins by small intestinal tissue of man and rat in vitro and the effect of endotoxin in the rat in vivo.

Rat jejunal tissue in vitro synthesizes large amounts of prostaglandin (PG) D2 and smaller amounts of 6-keto-PGF1 alpha and PGE2, whereas human small intestinal mucosa synthesizes much smaller amounts of the three PG determined with about equal amounts of PGE2 and PGD2. Intraperitoneal administration of bacterial endotoxin to rats induce fluid accumulation in the small intestine and increases significantly the release of PGD2, PGE2 and 6-keto-PGF1 alpha into the small intestinal lumen in vivo. Endotoxin-induced stimulation of PG release is particularly pronounced for PGD2. Fluid accumulation and PG output are inhibited by indomethacin. It seems possible that the different total amounts of PG synthesized by small intestinal tissue of man and rat as well as the different pattern of PG released might contribute to species-specific responses of the gastrointestinal tract to various pathophysiological stimuli.