Figure 2.

Summary of the cell sources in rodents and humans that have been successfully differentiated into Leydig-like cells in vitro. Differentiation was done by forced expression of transcription factors (Expression of TF), induction by defined chemical medium (Defined medium), or a combination of the two (Combinational). Some of the resulting cells were tested in vivo by their transplantation either into the testes of model animals, or in locations outside the testis. SC, stem cell; MSC, mesenchymal stem cell.