Insulin-like growth factor I and insulin induce adipogenic-related gene expression in fetal brown adipocyte primary cultures

T TERUEL, AM VALVERDE, M BENITO… - Biochemical …, 1996 - portlandpress.com
T TERUEL, AM VALVERDE, M BENITO, M LORENZO
Biochemical Journal, 1996portlandpress.com
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 dehydrogenase 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 …
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 dehydrogenase 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.
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