title: Effects of leptin on lipid metabolism and gene expression of differentiation-associated growth factors and transcription factors during differentiation and maturation of 3T3-L1 preadipocytes.
abstract: The present study was designed to determine the effects of leptin on lipid metabolism and gene expression during differentiation and maturation of the 3T3-L1 murine preadipocyte. The preadipocytes were induced to differentiate in a growth medium containing 10% calf serum and a hormonal cocktail for 2 days. The cells were next allowed to maturate for 14 days in the growth medium supplemented with 10 microg/ml insulin or 500 ng/ml insulin-like growth factor (IGF)-I in the absence or presence of supplemented leptin. Leptin, at a dose of 5 to 500 ng/ml, had no effect on proliferation of undifferentiated 3T3-L1 cells. However, leptin suppressed the insulin- or IGF-I-stimulated lipid accumulation and enhanced the release of glycerol, a measure of lipolysis, in a dose-dependent manner during and after the maturation of the cell. Moreover, leptin at a dose of 50 ng/ml inhibited IGF-I gene expression during the entire differentiation and maturation and also peroxisome proliferator activated receptor (PPAR)-gamma expression during late maturation as monitored by semi-quantitative reverse transcription-polymerase chain reaction. However, leptin exerted no effect on the expression of transforming growth factor-beta, CCAT/enhancer binding protein-alpha and PPAR-delta. Taken together, results suggest the anti-lipogenic and lipolytic effects of leptin in differentiating and mature adipocytes may have been partly mediated by suppressing the expression of PPAR-gamma and IGF-I genes.
authors.affiliation: Division of Biotechnology, College of Biosciences and Biotechnology, Korea University, Seoul.
authors.forename: Won Kon
authors.initials: WK
authors.lastname: Kim
authors.forename: Chul Young
authors.initials: CY
authors.lastname: Lee
authors.forename: Moon Sung
authors.initials: MS
authors.lastname: Kang
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Kim
authors.forename: Yang Hwan
authors.initials: YH
authors.lastname: Ryu
authors.forename: Kwang-Hee
authors.initials: KH
authors.lastname: Bae
authors.forename: Sung Jae
authors.initials: SJ
authors.lastname: Shin
authors.forename: Sang Chul
authors.initials: SC
authors.lastname: Lee
authors.forename: Yong
authors.initials: Y
authors.lastname: Ko
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D002455:Cell Division / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects*; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000494:pharmacology; D020738:Leptin / Q000008:administration & dosage / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects*; D008066:Lipolysis / Q000187:drug effects; D051379:Mice; D047495:PPAR gamma / Q000235:genetics
chemical_list: D007328:Insulin; D020738:Leptin; D047495:PPAR gamma; D007334:Insulin-Like Growth Factor I