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Updated: Aug 9, 2026

Quantitative Determination of De Novo Fatty Acid Synthesis in Brown Adipose Tissue Using Deuterium Oxide
Published on: May 12, 2023
Sterol regulatory element binding protein (SREBP)-1 expression in brain is affected by age but not by hormones or
Kenjirou Okamoto1, Tetsuya Kakuma, Satoshi Fukuchi
1Department of Internal Medicine 1, Oita University, Faculty of Medicine, Oita University, Hasama, Oita 879-5593, Japan.
Abstract:
Sterol regulatory element binding protein (SREBP)-1 is a membrane-bound transcription factor that regulates the expression of several genes involved in cellular fatty acid synthesis in the peripheral tissues, including liver. Although SREBP-1 is expressed in brain, little is known about its function. The aim of the present study was to clarify the characteristics of SREBP-1 mRNA expression in rat brain under various nutritional and hormonal conditions. In genetically obese (fa/fa) Zucker rats, expression of SREBP-1 mRNA was greater in liver than in hypothalamus or cerebrum compared to the lean littermates of these rats. Fasting for 45 h and refeeding for 3 h did not affect expression in brains of Wistar rats of SREBP-1 mRNA or the mRNAs of lipogenic enzymes that are targets of SREBP-1, i.e., fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC). Infusion of 2.0 mIU insulin or 3.0 microg leptin into the third cerebroventricle did not affect SREBP-1 mRNA expression in either hypothalamus or cerebrum. SREBP-1 mRNA expression in brains of transgenic mice that overexpressed leptin did not differ from that of wild-type mice. However, we observed a unique age-related alteration in SREBP-1 mRNA expression in brains of Sprague-Dawley rats. Specifically, SREBP-1 mRNA expression increased between 1 and 20 months of age, while there was no such change in the expression of FAS or ACC. This raises the possibility that increased SREBP-1 expression secondary to aging-related decline of polyunsaturated fatty acid (PUFA) might compensate for the reduction of FAS expression in brain. These findings suggest that the expression of SREBP-1 and downstream lipogenic enzymes in brain is probably not regulated by peripheral nutritional conditions or humoral factors. Aging-related changes in SREBP-1 mRNA expression may be involved in developmental changes in brain lipid metabolism.
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