Differences in mRNA expression of adipocyte-derived factors in response to fasting, refeeding and leptin.
The present study examines whether and to what extent the profiles of adipose-derived factors are altered in epididymal and subcutaneous adipose tissues of long-term fasted/refed and of fasted rats treated by recombinant leptin. Fasting was characterized by three successive metabolic phases. Minor differences in the time-course and magnitude of response were detected between the two adipose sites. Leptin, adiponectin, resistin, adiponutrin, and insulin-like growth factor-1 (IGF-1) gene expressions differentially decreased according to the fasting duration. mRNA levels reached a minimum in late fasting for these secreted factors, being decreased by 60-90% for adiponectin, resistin, and IGF-1, 95-98% for leptin and by 100% for adiponutrin. Refeeding partially or totally restored their mRNA expression in epididymal adipose. Expression levels of apolipoprotein E (ApoE), angiotensinogen (AGT), adipsin and macrophage migration inhibitory factor (MIF) were either unchanged or slightly affected. In leptin-treated rats, leptin mRNA concentrations were significantly decreased in phase 2 of fasting (by 85%) from levels in control phosphate-buffered saline (PBS)-treated rats in both tissues. Leptin treatment also decreased resistin mRNA levels (by 78% in P2L and 63% in P3L relative to control groups) in subcutaneous adipose. These data suggest that adiponectin, resistin, adiponutrin, and IGF-1 could be involved in overall energy homeostasis during prolonged fasting, as leptin is. The mechanisms that underlie the expressions of these adipose-secreted factors remain to be determined.
Bertile
Fabrice
F
Centre d'Ecologie et Physiologie Energétiques, UPR 9010 CNRS, Associé à l'Université Louis Pasteur, 23 rue Becquerel, 67087 Strasbourg Cedex 2, France. Fabrice.Bertile@c-strasbourg.fr
Raclot
Thierry
T
D052242:Adiponectin; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D004435:Eating; D004822:Epididymis; D005215:Fasting; D006729:Hormones, Ectopic / Q000235:genetics* / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D052243:Resistin; D014508:Urea / Q000652:urine
D052242:Adiponectin; D006729:Hormones, Ectopic; D036341:Intercellular Signaling Peptides and Proteins; D020738:Leptin; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger; D052243:Resistin; C499622:Retn protein, rat; C436316:adiponutrin; D007334:Insulin-Like Growth Factor I; D014508:Urea; D009584:Nitrogen