In vitro inhibition by mammal erythrocytes on erythropoiesis

Packed mammal erythrocytes of the same mass but characterised by different mean corpuscolar volumes (MCV) were incubated. The influence of these conditioned media (ECM) on⁵⁹Fe uptake into haem in cultures of guinea-pig bone-marrow cells was studied. The present results demonstrate that ram erythrocyte ECM (MCV = 28) caused a more marked in vitro depression of haeme synthesis than did calf (MCV = 34) and guinea pig (MCV = 69) erythrocyte ECM and that this inhibitory effect is correlated to the MCV of the erythrocytes considered.