Immunoautographic study of the synthesis of an ecdysteroid amplified protein in a Drosophila cell line and a clone in vitro

Drosophila mehznogaster cell lines maintained in vitro for several years [l] have retained their original diploid character. They are reliable material for the study of hormone action at the cellular level, with the advantage of an hormonal virgin background over in vivo or in vitro explanted tissue experiments. Ecdysteroids, the molting hormones controlling, insect development, have been shown to produce in vitro on Drosophila cell lines, morphological neuromimetic changes, agglutination of cells [2-41 and inhibition of cell proliferation [S-8]. After 20-hydroxyecdysone @I-ecdysone) treatment of a clone selected from the Kc line, a protein was shown to be induced after 3 days of steroid action, and was separated by electrophoresis on a non-denaturing gel [9]. Specific immune sera were elicited in rabbits injected with the protein gel band appearing after &ecdysone stimulation [ lo]. To study if the steroid effect was a protein induction or an amplification and if it was an early or a late effect of the hormone, we studied its time-course of synthesis, using an immunoautoradiographic method quantified through densitometric scanning.