[Differentiation of erythroid progenitors in organ cultures of mouse embryonal liver].

To study the reasons for the failure of erythroid differentiation in a long-term organ culture of mouse embryonal liver, the development of erythroid colony-forming progenitors was examined. The "early" (BFUei) and "late" (CFUei) erythropoietin-independent erythroid progenitors were present in washes from organ cultures for at least 56 days and in the "rests" of the cultures for 46 days. The mean concentration and the correlation of the "early" and "late" progenitors were similar to those in the bone marrow and initial embryonal liver. The data suggest that the stopping of erythroid differentiation in organ culture of embryonal liver occurs after CFUei formation, interfering with their maturation to morphologically recognizable erythroid cells.