Vitellogenin synthesis in female larvae of the gypsy moth, Lymantria dispar (L.): suppression by juvenile hormone

1. 1. Fat body from feeding-phase, last instar gypsy moth females incorporates l-[³⁵S]methionine in vitro into two vitellogenins with the same molecular masses (165 and 180 kDa) as the apo-vitellogenins found in teh hemolymph and the apo-vitellins in teh eggs. 2. 2. Both apo-vitellogenins are observed in the medium of fat body cultures, but only the 180 kDa apo-vitellogenin is observed in extracts of cultured tissue. 3. 3. Synthesis and accumulation of the apo-vitellogenins are suppressed in a dose-dependent manner by topical treatment with the juvenile hormone analog, methoprene, prior to day 4. 4. 4. This suppression suggests that a declining juvenile hormone titre is involved in the initiation of vitellogenin synthesis.