Growing in Antarctica, a challenge for white adipose tissue development in Adelie penguin chicks (Pygoscelis adeliae).
Rapid growth is of crucial importance for Adélie penguin chicks reared during the short Antarctic summer. It partly depends on the rapid ontogenesis of fat stores that are virtually null at hatching but then develop considerably (x40) within a month to constitute both an isolative layer against cold and an energy store to fuel thermogenic and growth processes. The present study was aimed at identifying by RT-PCR the major transcriptional events that chronologically underlie the morphological transformation of adipocyte precursors into mature adipocytes from hatching to 30 days of age. The peak expression of GATA binding protein 3, a marker of preadipocytes, at day 7 posthatch indicates a key proliferation step, possibly in relation to the expression of C/EBPalpha (C/EBPalpha). High plasma total 3,5,3'-triiodo-l-thyronine (T(3)) levels and high levels of growth hormone receptor transcripts at hatching suggested that growth hormone and T(3) play early activating roles to favor proliferation of preadipocyte precursors. Differentiation and growth of preadipocytes may occur around day 15 in connection with increased abundance of transcripts encoding IGF-1, proliferator-activated receptor-gamma, and C/EBPbeta, gradually leading to functional maturation of metabolic features of adipocytes including lipid uptake and storage (lipoprotein lipase, fatty-acid synthase) and late endocrine functions (adiponectin) by day 30. Present results show a close correlation between adipose tissue development and chick biology and a difference in the scheduled expression of regulatory factors controlling adipogenesis compared with in vitro studies using cell lines emphasizing the importance of in vivo approaches.
Raccurt
Mireille
M
UMR CNRS 5123, Laboratoire de Physiologie Intégrative Cellulaire et Moléculaire, Bâtiment Raphaël Dubois, 4étage, Université Claude Bernard Lyon1, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne cedex. mireille.raccurt@univ-lyon1.fr
Baudimont
Fannie
F
Tirard
Julien
J
Rey
Benjamin
B
Moureaux
Elodie
E
Géloën
Alain
A
Duchamp
Claude
C
D017667:Adipocytes / Q000502:physiology; D052436:Adipose Tissue, White / Q000254:growth & development* / Q000502:physiology; D000375:Aging / Q000502:physiology; D000818:Animals; D000864:Antarctic Regions; D001833:Body Temperature Regulation / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D017931:DNA Primers; D050980:GATA Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D020869:Gene Expression Profiling; D009929:Organ Size / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046429:Spheniscidae / Q000254:growth & development*; D014157:Transcription Factors / Q000235:genetics; D014284:Triiodothyronine / Q000097:blood
D017931:DNA Primers; D050980:GATA Transcription Factors; D012333:RNA, Messenger; D014157:Transcription Factors; D014284:Triiodothyronine