PLEIOTROPIC EFFECTS OF TRYPSIN MODULATING OOSTATIC FACTOR (NEB-TMOF) OF THE FLESHFLY NEOBELLIERIA-BULLATA (DIPTERA, CALLIPHORIDAE)

Trypsin Modulating Oostatic Factor (TMOF) of the grey fleshfly Neobell ieria bullata is a hexapeptide that has been isolated from vitellogeni c ovaries. Its precursor is a 75 kDa protein that is abundantly presen t in oocytes but absent from hemolymph. TMOF inhibits trypsin biosynth esis in the gut, it lowers yolk polypeptide concentration in the hemol ymph and strongly inhibits ecdysone biosynthesis by larval ring glands . Evidence is presented that a molecule with identical chromatographic behaviour and physiological effects is also present in the larvae of Neobellieria at the time when they stop feeding, Ecdysone inhibition d oes not suppress trypsin modulating activity of the hexapeptide. This, in combination with results that were obtained with four slightly dif ferent TMOF analogs, suggests that the inhibitory activity of trypsin biosynthesis is independent from that of ecdysone regulation. Several compounds that were tested for initiation or increase in trypsin biosy nthesis in the gut were not active.