Insulin-like growth factor I and insulin induce adipogenic-related gene expression in fetal brown adipocyte primary cultures.
Fetal rat brown adipocytes show high-affinity binding sites for both insulin-like growth factor I (IGF-I) and insulin. Cell culture for 24 h in the presence of IGF-I or insulin, independently, up-regulated the mRNA expression of adipogenic-related genes, such as fatty acid synthase (FAS), glycerol-3-phosphate de-hydrogenase and insulin-regulated glucose transporter Glut4, and down-regulated the expression of phosphoenolpyruvate carboxykinase mRNA in a dose-dependent manner. Moreover, both IGF-I and insulin increased the FAS gene transcription rate at 2 h, producing a time-dependent accumulation of FAS mRNA. Furthermore IGF-I or insulin increased glucose uptake and lipid content throughout the 24 h culture period. Our results suggest that both IGF-I and insulin are major signals involved in initiating and/or maintaining the expression of adipogenic-related genes in fetal rat brown adipocytes.
Departamento de Bioquímica y Biología Molecular II, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
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T
Teruel
A M
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Valverde
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M
Benito
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M
Lorenzo
D002001:Adipose Tissue, Brown / Q000196:embryology / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D064429:Fatty Acid Synthases / Q000096:biosynthesis; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D051275:Glucose Transporter Type 4; D005993:Glycerolphosphate Dehydrogenase / Q000096:biosynthesis; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis; D009124:Muscle Proteins; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar
D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495694:Slc2a4 protein, rat; D007334:Insulin-Like Growth Factor I; D005993:Glycerolphosphate Dehydrogenase; D064429:Fatty Acid Synthases; D010729:Phosphoenolpyruvate Carboxykinase (GTP)