Consumption of soy protein isolate reduces hepatic SREBP-1c and lipogenic gene expression in wild-type mice, but not in FXR-deficient mice

Biosci Biotechnol Biochem. 2011;75(9):1702-7. doi: 10.1271/bbb.110224. Epub 2011 Sep 7.


We examined to determine whether hepatic gene expression is affected in mice in which blood lipid levels remain unchanged fed soy protein isolate (SPI) for a short time. We also examined SPI-mediated effects in farnesoid X receptor (FXR)-deficient mice. Compared with casein, SPI affected the expression of various hepatic genes related to lipid metabolism in the wild-type mice. No effects of SPI were observed in the FXR-deficient mice, suggesting the importance of FXR. Hepatic peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) gene expression was reduced by SPI, and this might be associated with a decrease in FXR expression. Decreased FXR led to decreased expression of its target, the bile-salt export pump necessary for bile acid secretion and dietary lipid absorption. The earliest response to SPI was a decrease in hepatic sterol regulatory element-binding protein (SREBP)-1c mRNA, on day 3. SPI activated hepatic adenosine monophosphate-activated protein kinase (AMPK), which can lead to a reduction in SREBP-1c mRNA. These data indicate the importance of SREBP-1c and PGC-1α/FXR in SPI-mediated alterations in hepatic gene expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism
  • Animals
  • Down-Regulation / drug effects
  • Enzyme Activation / drug effects
  • Gene Expression Regulation / drug effects*
  • Lipogenesis / drug effects*
  • Liver / cytology
  • Liver / drug effects*
  • Liver / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • PPAR gamma / genetics
  • PPAR gamma / metabolism
  • RNA, Messenger / analysis
  • RNA, Messenger / biosynthesis
  • Real-Time Polymerase Chain Reaction
  • Receptors, Cytoplasmic and Nuclear / deficiency*
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Soybean Proteins / metabolism
  • Soybean Proteins / pharmacology*
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism


  • PPAR gamma
  • RNA, Messenger
  • Receptors, Cytoplasmic and Nuclear
  • Soybean Proteins
  • Sterol Regulatory Element Binding Protein 1
  • farnesoid X-activated receptor
  • AMP-Activated Protein Kinases