Farnesoic acid as a major product of release from crustacean mandibular organs in vitro

Abstract

Abstract Incubation of mandibular organs (MO) from the crab Scylla serrata with medium containing [2‐ 14 C]‐acetate and [methyl‐ 3 H]‐methionine results in the biosynthesis and release of, predominantly, farnesoic acid and of methyl farnesoate. The identity of each was confirmed by liquid chromatography and gas chromatography/mass spectrometry (GS/MS). Farnesoic acid is released into the incubation medium at a rate tenfold greater than methyl farnesoate. Release of the acid was linear over an 8‐hr incubation period. However, the amount of farnesoic acid within the MO did not equal the quantity of methyl farnesoate in the glands. Analysis of haemolymph extracts by GC/MS confirmed the presence of methyl farnesoate but farnesoic acid was not detected. These data suggest that farnesoic acid is released by the MO of S. serrata and either rapidly metabolized or sequestered by the tissues. It is possible that farnesoic acid may be a prohormone and converted into other isoprenoid products.