Just the Right Size

Science's STKE  01 Nov 2005:
Vol. 2005, Issue 308, pp. tw387
DOI: 10.1126/stke.3082005tw387

Two parameters control the eventual size of insects: their growth rate and the length of their growth period. Ecdysone, a major steroid hormone, functions as a developmental timer that controls the length of the growth period. Colombani et al. (see the Perspective by King-Jones and Thummel) now show that ecdysone from the prothoracic gland of Drosophila also regulates the speed at which the animals grow by inhibiting insulin/insulin-like growth factor signaling. This work provides a conceptual framework for understanding how the final size of an organism is determined and establishes a link between steroid hormone and insulin signaling.

J. Colombani, L. Bianchini, S. Layalle, E. Pondeville, C. Dauphin-Villemant, C. Antoniewski, C. Carré, S. Noselli, P. Léopold, Antagonistic actions of ecdysone and insulins determine final size in Drosophila. Science 310, 667-670 (2005). [Abstract] [Full Text]

K. King-Jones, C. S. Thummel, Less steroids make bigger flies. Science 310, 630-631 (2005). [Summary] [Full Text]