title: The effects of concentrations of lysine in media on differentiation of 3T3-L1 preadipocytes.
abstract: Intramuscular fat content is increased by feeding of low lysine diets in pigs. Reduction in dietary lysine intake results in low plasma lysine concentration and low cytosolic lysine concentration in skeletal muscles. From these observations, we hypothesized that low plasma lysine concentration in pigs fed on low lysine diets reduced supply of lysine from blood circulation to preadipocytes, and this limited supply of lysine might promote adipocyte differentiation in porcine muscles. In order to verify the hypothesis, we investigated the effects of low concentrations of lysine in culture medium on differentiation of 3T3-L1 preadipocytes. Low concentration of lysine suppressed lipid accumulation and messenger RNA (mRNA) expression and enzyme activity of fatty acid synthase. mRNA expressions of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) were lower in cells cultured in low lysine medium. On the other hand, mRNA and protein expressions of C/EBPβ and C/EBPδ were not inhibited by low concentrations of lysine in culture medium. These results indicate that low lysine concentrations in culture medium inhibit differentiation of 3T3-L1 preadipocytes through inhibiting the mRNA expressions of PPARγ and C/EBPα.
authors.affiliation: United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Kyoya
authors.forename: Aiko
authors.initials: A
authors.lastname: Ishida
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nakashima
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Nakajima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Toyoda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Masaya
authors.initials: M
authors.lastname: Katsumata
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D015153:Blotting, Western; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000032:analysis; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000032:analysis; D051743:CCAAT-Enhancer-Binding Protein-delta / Q000032:analysis; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D003470:Culture Media; D008055:Lipids / Q000032:analysis; D008239:Lysine / Q000008:administration & dosage* / Q000494:pharmacology; D051379:Mice; D047495:PPAR gamma / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D013552:Swine / Q000502:physiology*
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D022782:CCAAT-Enhancer-Binding Protein-beta; D003470:Culture Media; D008055:Lipids; D047495:PPAR gamma; D012333:RNA, Messenger; D051743:CCAAT-Enhancer-Binding Protein-delta; D008239:Lysine