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.
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.
Kim
Won Kon
WK
Division of Biotechnology, College of Biosciences and Biotechnology, Korea University, Seoul.
Lee
Chul Young
CY
Kang
Moon Sung
MS
Kim
Min Ho
MH
Ryu
Yang Hwan
YH
Bae
Kwang-Hee
KH
Shin
Sung Jae
SJ
Lee
Sang Chul
SC
Ko
Yong
Y
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
D007328:Insulin; D020738:Leptin; D047495:PPAR gamma; D007334:Insulin-Like Growth Factor I