ation of the growth factor Activin A with n-butyrate or the combination of retinoic acid (RA) and enriching agents (e.g. selenium and thyroid hormone, such as T3) to generate endoderm cells from pluripotent stem cells, and a second step of culturing the endoderm cells with a combination of TGF-(antagonists such as Nogin, and mitogens such as FGF family members such as EGF) to generate Pdx1-positiv