Co-treatment with dexamethasone and octanoate induces adipogenesis in 3T3-L1 cells.
We report here that octanoate, a medium chain fatty acid, induces adipocyte differentiation in 3T3-L1 cells by co-treatment with dexamethasone, although octanoate has been known not to stimulate 3T3-L1 adipogenesis. A low concentration of exogenous glucose prevented 3T3-L1 adipogenesis induced by 1-methyl 3-isobutylxanthine, dexamethasone, and insulin (MDI) treatment (a common protocol for adipocyte differentiation). In contrast, co-treatment with dexamethasone and octanoate (D-OCT) induced adipogenesis under the same conditions. These findings imply that octanoate, rather than glucose, is the source of accumulated lipids in D-OCT-induced adipogenesis. D-OCT increased expression of the differentiation markers peroxisome proliferator-activated receptor (PPAR)gamma2 and caveolin-1. A specific inhibitor of p38 mitogen-activated protein (MAP) kinase inhibited D-OCT-induced adipogenesis. These results suggest that the p38 MAP kinase pathway followed by up-regulation of PPARgamma2 may be involved in 3T3-L1 adipocyte differentiation induced by D-OCT, as well as by MDI.
Takenouchi
Takato
T
Functional Biomolecule Laboratory, National Institute of Livestock and Grassland Science, Ikenodai 2, Tsukuba, Ibaraki 305-0901, Japan. ttakenou@affrc.go.jp
Takayama
Yoshiharu
Y
Takezawa
Toshiaki
T
D041721:3T3-L1 Cells; D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002210:Caprylates / Q000494:pharmacology*; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D003907:Dexamethasone / Q000494:pharmacology*; D005938:Glucocorticoids / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases
D002210:Caprylates; C495541:Cav1 protein, mouse; D051242:Caveolin 1; D022461:Caveolins; D005938:Glucocorticoids; D007093:Imidazoles; D011725:Pyridines; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D003907:Dexamethasone; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose; C031492:octanoic acid; C093642:SB 203580