Active ion transport and beta-acdysone induced differentiation of Drosophila melanogaster imaginal discs cultured in vitro

J Embryol Exp Morphol. 1977 Feb;37(1):119-31.


The theory that beta-ecdysone initiates developmental changes during insect metamorphosis by causing an increase in intranuclear levels of potassium, together with a concomitant decrease in sodium levels, has been investigated by two methods. First, imaginal discs from late third instar larvae have been cultured with 0-2 microng/ml of beta-ecdysone together with inhibitors of active ion transport. Non-specific inhibitors, which may have general effects on sulphydryl groups, such as iodoacetic acid, N-ethylmaleimide ethacrinic acid and furosemide, inhibit both eversion and differentiation at concentrations of from 10(-3) M to 2 X 10(-3) M. Ouabain, the only specific inhibitor of the active transport of Na+ and K+ across membranes, had no effect on development even at a concentration of 10(-2) M. Second, a medium containing raised levels of K+, and reduced concentrations of Na+, neither initiated disc development in the absence of beta-ecdysone, nor stimulated development induced by suboptimal levels (0-02 microng/ml) of beta-ecdysone, either in the presence or absence of ouabain. These results suggest that beta-ecdysone induced morphogenesis is not dependent upon Na+ and K+ concentrations, or on the activity of an ouabain-sensitive ion pump.

MeSH terms

  • Animals
  • Biological Transport, Active / drug effects
  • Cell Differentiation / drug effects
  • Drosophila melanogaster / embryology*
  • Ecdysone / pharmacology*
  • Extremities / drug effects
  • Extremities / embryology
  • In Vitro Techniques
  • Morphogenesis / drug effects
  • Potassium / metabolism
  • Sodium / metabolism
  • Wings, Animal / drug effects
  • Wings, Animal / embryology


  • Ecdysone
  • Sodium
  • Potassium