Transforming growth factorβ1 induces differentiation‐specific gene expression in fetal rat brown adipocytes

Abstract
Fetal rat brown adipocytes show a low number of transforming growth factorβ1 (TGF-β1) binding sites of high affinity, revealing the presence of type I, II and IIITGF-β1 receptors and a minor-labeled species of approximately 140 kDa. The culture of cells in the presence ofTGF-β1 induced the expression of the tissue-specific gene uncoupling protein in a dose- and time-dependent manner. In addition,TGF-β1 up-regulates the expression of genes involved in adipogenesis such as fatty acid synthase, glycerol 3-phosphate dehydrogenase, malic enzyme and glucose 6-phosphate dehydrogenase, as well as induces the expression of fibronectin (specific target gene forTGF-β1). Our results suggest thatTGF-β1 is a major signal involved in initiating and/or maintaining the thermogenic and adipogenic differentiation of rat fetal brown adipocytes