Mouse serum enables CFU-E to grow under physiologic concentration of erythropoietin in vitro

Addition of normal mouse serum to cultures of mouse CFU-Es, not only increases the number of colonies as we recently reported (Blanchet et al. 1984), but also enhances the sensitivity of mouse CFU-Es to erythropoietin so that physiologic concentrations can be used with optimal colony development. These results were obtained as well with porcine or murine Epo. Thus, NMS exerts a stimulating and facilitating effect on CFU-E development. The stimulating activity was less resistant to heat treatment than was the facilitating one, an indication that both activities may be mediated by different molecules.