Ecdysteroid and Juvenile Hormone Binding Proteins are regulated during Vitellogenic Development in Drosophila melanogaster.

Stacy Cerula, Adam Horst, J. Paul Detweiler, Jennifer M. Jones and David S. Richard, Department of Biology, Susquehanna University, Selinsgrove, PA 17870-1164. To be presented to the Pennsylvania Academy of Science meeting, April, 1999.

Vitellogenesis in Drosophila melanogaster is driven by the endocrine system such that 20­hydroxyecdysone and the juvenile hormones (JHs) interact to orchestrate synthesis and uptake by developing oocytes of yolk proteins. Our recent studies have challenged the notion that the JHs play the primary role in these processes and data shows the ecdysteroids to be more important. While determinations of circulating hormone levels are necessary we also need information on their active binding protein/receptor levels. These were determined in female Drosophila melanogaster using equilibrium dialysis techniques with radiolabeled ligands during normal development following eclosion, and during the termination of a photoperiodic female-reproductive diapause by both warming and by hormone injection. These data together with determinations of the levels of receptors to both hormones in JH-deficient, yet vitellogenic, mutant apterous56f females further supports our model in which ecdysteroids and not JHs drive YP uptake. (Supported in part by NIH GM/OD54905, to DSR).