Roles of juvenile hormone, a brain factor and adipokinetic hormone in regulation of vitellogenin biosynthesis in locusta migratoria.

In maturing adult female migratory locusts, the rises in JH and Vg in the hemolymph are greatly accelerated by enriched feeding; hereafter the JH titer fluctuates with vitellogenic cycles, falling to a low level at the oviposition stage. In fat bodies incubated in vitro, the JH analog, methoprene, and brain extract from well-fed locusts (but not starved locusts) stimulated Vg synthesis synergistically. Repeated washing of fat bodies from oviposition stage locusts led to a rise in Vg synthesis after 4 h, which was prevented by addition of locust adipokinetic hormone (AKH). We conclude that at least three hormonal factors interact in the control of Vg synthesis in locus fat body: JH and a brain factor stimulate, reflecting development and nutrition, while AKH inhibits at the oviposition stage.