[Comparison of the effects of alpha and beta ecdysone on a diploid clone of cultured Drosophila melanogaster cells in vitro: induction of proteins and morphological changes]

Abstract

The specific induction of a similar (class of) protein(s) by alpha or beta-ecdysone in the cells of a "sensitive" clone of Drosophila melanogaster cultured in vitro was shown by polyacrylamide gel electrophoresis. However, differences can be seen in the action of the two hormones. (1) The threshold concentration is about 10 times higher for alpha-ecdysone (10 nM) than for beta-ecdysone (1 nM). (2) Beyond this threshold (i.e. 100 nM) the rate of induction is greater for beta-ecdysone (less than or equal to 24 h) than for alpha-ecdysone (larger than or equal to 48 h). The morphological modifications and the protein induction are seen simultaneously after 1 day of 100 nM beta-ecdysone treatment. On the contrary, a dissociation of these two phenomena is noted with the same concentration of alpha-ecdysone.