Transforming growth factor type beta is a specific inhibitor of 3T3 T mesenchymal stem cell differentiation.

In the current studies we examined the effects of transforming growth factor type beta (TGF-beta) on the control of differentiation of BALB/c 3T3 T stem cells. We report that TGF-beta is a potent, reversible inhibitor of adipocyte differentiation (50% inhibition at approximately 0.06-0.08 ng/ml), while other biologically active polypeptides, such as epidermal growth factor (EGF), human growth hormone (hGH), and somatomedin C, have no specific effect on differentiation at even higher concentrations (200 ng/ml). We also report that TGF-beta inhibits differentiation in a cell cycle-dependent manner by its effect on a specific phase in the differentiation process. We therefore suggest that if TGF-beta is an important regulatory factor, one of its critical mechanisms of action may be its ability to inhibit the process of cell differentiation.