Comparison of the expression and activity of the lipogenic pathway in human and rat adipose tissue.
Lipogenesis is considered less active in human than in rat adipose tissue. This could be explained by different nutritional conditions, namely high-carbohydrate (HCHO) diet in rats and high-fat (HF) diet in humans. Adipose tissue was sampled (postabsorptive state) in rats and humans receiving HCHO or HF diets, ad libitum fed humans, and obese subjects. We measured 1) mRNA concentrations of fatty acid synthase (FAS), acetyl-CoA carboxylase 1 (ACC1), sterol regulatory element binding protein 1c (SREBP-1c), and carbohydrate response element binding protein (ChREBP), 2) SREBP-1c protein, and 3) FAS activity. FAS, ACC1, ChREBP, and SREBP1-c mRNA concentrations were unaffected by diet in humans or in rats. FAS and ACC1 mRNA levels were lower in humans than in rats (P < 0.05). FAS activity was unaffected by diet and was lower in humans (P < 0.05). SREBP-1c mRNA concentrations were similar in rats and humans, but the precursor and mature forms of SREBP-1c protein were less abundant in humans (P < 0.05). ChREBP mRNA concentrations were lower in humans than in rats. In conclusion, the lipogenic capacity of adipose tissue is lower in humans than in rats. This is not related to differences in diet and is probably explained by lower abundance of SREBP-1c protein. A decreased expression of ChREBP could also play a role.
Letexier
Dominique
D
INSERM U 499, Faculté RTH Laennec, 69008 Lyon, France.
Pinteur
Claudie
C
Large
Valérie
V
Fréring
Vincent
V
Beylot
Michel
M
D000103:Acetyl-CoA Carboxylase / Q000235:genetics; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D015992:Body Mass Index; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism; D003067:Coenzymes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D008055:Lipids / Q000096:biosynthesis*; D008099:Liver / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors / Q000235:genetics
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D022762:CCAAT-Enhancer-Binding Proteins; D003067:Coenzymes; D004268:DNA-Binding Proteins; D008055:Lipids; C442825:Mlxipl protein, rat; D012333:RNA, Messenger; C497387:SREBF1 protein, human; C497389:Srebf1 protein, rat; D051780:Sterol Regulatory Element Binding Protein 1; D014157:Transcription Factors; D064429:Fatty Acid Synthases; D000103:Acetyl-CoA Carboxylase