Physiology

Not Fat, Just Well Covered

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Science  24 Oct 2008:
Vol. 322, Issue 5901, pp. 506
DOI: 10.1126/science.322.5901.506d

Adélie penguins breed on the Antarctic ice, and the chicks, to survive, must rapidly establish a layer of fat to protect themselves against the subzero temperatures and to enable them to enter the water a mere 2 months after hatching. Raccurt et al. investigated the transcriptional program responsible for this speedy production of adipose tissue by taking autopsy samples from the chicks of 16 out of the 34,000 penguin pairs that breed on the Pointe Geologie archipelago. They then measured the expression levels of transcription factors, hormone receptors, and other genes known from in vitro studies of mouse and chicken cells to be involved in the growth and differentiation of adipocytes. In the first 2 weeks, while a chick was at least partially protected by sheltering in a parent's brood pouch, growth hormone and 3,5,3′-triiodo-thyronine (T3) receptors along with the transcription factor GATA3 marked a period of intensive adipocyte differentiation and development. After day 15, when chicks had outgrown their brood pouches, lipoprotein lipase, PPARγ, and other factors associated with adipocyte maturation and lipid storage took over to produce large fat-filled cells that formed a thermally insulating layer. This is similar to the changes seen in chicken cells, but subtle differences demonstrate how in penguins that pattern is tailored to their particular habitat. — CS*

Am. J. Physiol. Regul. Integr. Comp. Physiol. 295, 10.1152/ajpregu.90371.2008 (2008).

  • *Chris Surridge is a locum editor in Science's editorial department.

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