Cuticle secretion in Drosophila wing imaginal discs in vitro: parameters of exposure to 20-hydroxy ecdysone.

We have cultured Drosophila wing imaginal discs in vitro under a variety of hormonal conditions in order to determine whether cuticle secretion is enhanced by a withdrawal of 20-hydroxy ecdysone at one of two points in development, corresponding to the drop in hormone titer during the prepupal period, and to the fall in hormone levels during the later stages if imaginal differentiation. We found that these treatments did not enhance either pupal or adult cuticle secretion.