Interaction between juvenile hormone, 20-hydroxyecdysone, the corpus cardiacum-allatum complex, and the ovaries in regulating vitellogenin levels in the housefly, Musca domestica

Abstract

This study examines the interaction between the ovaries, corpus cardiacum-allatum complex, juvenile hormone, and 20-hydroxyecdysone to either induce or regulate vitellogenin production in the housefly Musca domestica. All of the unoperated control flies contained vitellogenin and these levels were increased by the application of methoprene, a juvenile hormone analogue or 20-hydroxyecdysone. Flies without the corpus cardiacum-allatum complex had low vitellogenin levels, but these were restored to control amounts by treatment with methoprene, but not 20-hydroxyecdysone. Ovariectomized flies showed a steady increase in vitellogenin levels and only the treatment with 20-hydroxyecdysone increased the amounts of vitellogenin further. Flies without either the corpus cardiacum-allatum complex or the ovaries had undetectable amounts of vitellogenin, but treatment with methoprene gave a control pattern of vitellogenin, while 20-hydroxyecdysone treatment resulted in trace amounts of vitellogenin. In these studies only treatment with 20-hydroxyecdysone elevated vitellogenin to control levels if the corpus cardiacum-allatum complex was present. Treatment with methoprene elevated vitellogenin to control levels in flies without the corpus cardiacum-allatum complex. When ovariectomized insects without the corpus allatum-cardiacum complex were treated with 0.1 μg methoprene and 0.05 or 0.5 μg 20-hydroxyecdysone, vitellogenin levels were increased to control amounts, but neither hormone alone at these doses induced the appearance of vitellogenin. Thus it appears that the production of control levels of vitellogenin requires both juvenile hormone and 20-hydroxyecdysone.