Experiments in vitro have shown that 20-hydroxyecdysone (at a concentr
ation of 0.2 and 2 muM and after 12 and 24 hr of incubation) is able t
o induce the precocious deposition of chorion materials by the follicu
lar epithelium of young oocytes of the cockroach Blattella germanica.
Since previous studies had shown that 20-hydroxyecdysone levels in B.
germanica ovaries increase with oocyte maturation to reach a peak just
before oviposition, we therefore hypothesize that ovarian ecdysteroid
s trigger choriogenesis in this species through an autocrine action.