Abstract
The failure of one-cell embryos of non-inbred mouse (CD-1) to develop in vitro (2-cellblock) was examined by culture in a chemically defined (WM-HEPES) medium containing activin A (erythroid differentiation factor, EDF). Successful development of one-cell embryos into 4-cell embryos or morulae in the WM-HEPES medium was significantly enhanced in the presence of activin A. More than 83% of one-cell embryos developed into 4-cell embryos in the presence of 1.0 ng/ml activin A during the 2-cell stage in contrast with 15% in control cultures without activin A. This activity was most evident at the mid-2-cell stage. Eight of 40 embryos treated with activin A were delivered alive from the 2 recipient mothers 18 days later. This capacity of activin A to stimulate early embryonal development was also demonstrated in 8-cell embryos, the proportion of embryos developing to the morula stage being significantly promoted. Our results demonstrate the capacity of activin A to release the 2-cell block and to stimulate early embryonal development in vitro.
