Prostaglandin biosynthesis by fat body from true armyworms, Pseudaletia unipuncta

We describe prostaglandin (PG) biosynthesis by microsomal-enriched fraction s of fat body prepared from true armyworms, Pseudaletia unipuncta. PG biosy nthesis was sensitive to experimental conditions, including incubation time , temperature, pH, substrate and protein concentration. Optimal PG biosynth esis conditions included I mg of microsomal-enriched protein, incubated at 28 degreesC for 7.5 min at pH 8. These preparations yielded four major PGs: PGA(2), PGE(2), PGD(2) and PGF(2 alpha). PGA(2) and PGE(2) were the predom inant eicosanoids produced under these conditions. Two non-steroidal anti-i nflammatory drugs, indomethacin and naproxen, effectively inhibited PG bios ynthesis. Unlike other invertebrate PG biosynthetic systems studied so far, the true armyworm system appeared to be independent of the usual exogenous co-factors required by mammalian and other invertebrate systems. These fin dings are discussed with respect to PG biosynthesis in other invertebrate a nd vertebrate systems. (C) 2001 Published by Elsevier Science Ltd.