mRNA levels of SREBP-1c do not coincide with the changes in adipose lipogenic gene expression.
Physiological differences in lipid metabolism exist according to adipose sites. To delineate at which step such gene regulation could occur, mRNA levels of various proteins involved in the overall lipogenic process were determined in subcutaneous (SC) and retroperitoneal (RP) adipose tissues. Fatty acid synthase, malic enzyme, ATP citrate lyase, insulin-sensitive glucose transporter, and glucose-6-phosphate dehydrogenase mRNA levels were coordinately reduced (by up to 50-fold) during fasting in RP and in SC relative to fed rats, and restored or overexpressed (by up to 5- to 6-fold) during refeeding. The response was most often delayed and lower in SC compared to RP. This could contribute to site-specific differences. Interestingly, SREBP-1c mRNA levels were markedly decreased by fasting in SC but remained unchanged in RP. Refeeding tended to restore levels close to fed group values. We conclude that mRNA levels of SREBP-1c do not coincide with the expected changes in adipose lipogenic gene expression of fasted/refed rats.
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
D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005215:Fasting / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology; D050356:Lipid Metabolism; D008297:Male; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012187:Retroperitoneal Space / Q000502:physiology; D012867:Skin / Q000378:metabolism; D051780:Sterol Regulatory Element Binding Protein 1; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; C497389:Srebf1 protein, rat; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors