In vitro induction of UCP1 mRNA in preadipocytes from rabbit considered asa model of large mammals brown adipose tissue development: importance of PPAR gamma agonists for cells isolated in the postnatal period
B. Cambon et al., In vitro induction of UCP1 mRNA in preadipocytes from rabbit considered asa model of large mammals brown adipose tissue development: importance of PPAR gamma agonists for cells isolated in the postnatal period, MOL C ENDOC, 146(1-2), 1998, pp. 49-58
In mammals with a lower mass-specific metabolic rate than small laboratory
rodents, the brown adipose tissue (BAT) loses its thermogenic activity afte
r birth and undergoes a transformation into white adipose tissue (WAT). Rab
bit is a model of these mammals of larger body mass. Preadipocytes from cer
vical BAT of foetal or newborn rabbits differentiated in a chemically-defin
ed medium and expressed low levels of uncoupled protein-1 (UCP1) mRNA, grea
tly increased by beta 3-adrenergic or retinoic acid stimulations. On the co
ntrary, preadipocytes from 1-month-old animals differentiated in the same c
onditions with no detectable expression of UCP1. Peroxisome proliferator-ac
tivated receptor gamma (PPAR gamma) agonists were necessary to induce UCP1
in these cells from older animals, a synergistic increase being noted in th
e presence of beta 3-adrenergic agonists. In contrast to these results, pre
adipocytes from perirenal WAT stimulated by PPAR gamma agonists never expre
ssed UCP1. Conclusion: preadipocytes in the postnatal period are determined
as brown or white preadipocytes. PPAR gamma agonists induce UCP1 expressio
n in brown postnatal preadipocytes, but they are unable to trigger the gene
in white preadipocytes. (C) 1998 Elsevier Science Ireland Ltd. All rights
reserved.