Isoproterenol stimulation of heme synthesis in cultures of human fetal liver from early gestation.

The role of isoproterenol in the synthesis of heme associated with hemoglobin has been studied in primary cultures of human fetal liver. This drug (10-10M) stimulated the incorporation of 59Fe into heme associated with hemoglobin in cell cultures of livers obtained from human fetuses 8 to 10 weeks gestation but was inactive in cell cultures prepared from livers of older fetuses. Isoproterenol has its optimal activity at a much earlier time in gestation than that previously reported for testosterone or erythropoietin. The interpretation of these results is that there is present a cell population in human fetal liver early in gestation with the appropriate isoproterenol-receptors and capable of erythroid differentiation after exposure to the drug.