Inflammation of the guinea‐pig colon was produced by skin sensitization and subsequent intracolonic challenge with the chemical hapten, dinitrochlorobenzene.
Metabolism of [14C]‐arachidonic acid by homogenates of control colon was very low, although metabolites co‐migrating on thin layer chromatography (t.l.c.) with prostaglandin E2 (PGE2), PGF2α, PGD2, 6‐keto‐PGF1α, thromboxane B2 (TXB2), HHT and 11‐, 12‐, 15‐HETE were formed.
There was an overall 3 fold increase in metabolism of [14C]‐arachidonic acid by homogenates of inflamed mucosa. The greatest increase in metabolite formation was of PGE2, with smaller increases in HHT, 11‐, 12‐, 15‐HETE, PGD2, TXB2, PGF2α and 6‐keto‐PGF1α. The formation of these metabolites was inhibited both by indomethacin and the dual pathway inhibitor, BW755C.
The formation of immunoreactive PGE2, TXB2 and 6‐keto‐PGF1α was also increased in homogenates of inflamed guinea‐pig colon. The small level of immunoreactive LTB4 detected in control colon was not changed in inflamed colonic tissue.
The dinitrochlorobenzene model of colitis offers a means of studying arachidonic acid metabolism in an immune‐mediated inflammatory response in intestinal tissue.