Bioconversion of arachidonic acid in the human gastrointestinal tract

The data presented demonstrate that the bioconversion of [14C]arachidonic acid in homogenates like these is very easily influenced by protein (enzyme) and substrate concentration as well as exogenous cofactors. This is not unexpected but variations will lead to artifactual differences. Neither quantitative nor qualitative differences could be detected between biopsies taken from healthy as compared to diseased individuals. No products other than PGE2, PGF2 alpha, TxB2, and 6-keto-PGF1 alpha (and metabolites thereof) could be demonstrated although special efforts were undertaken to determine whether there was any detectable lipoxygenase activity. Therefore it seems that future studies on the possible roles of prostaglandins in gastrointestinal physiology should be restricted to those compounds identified, primarily PGE2 and PGF2 alpha. The monotony in the pattern of products formed in homogenates from different tissues also suggests that in order to be able to detect possible differences between various conditions such studies should involve a minimum of tissue manipulation.