The role of cyclic nucleotide on fetal and neonantal erythropoiesis

For the purpose to reveal the changes in stimulatory effect of dibutyryl-cyclic- AMP on erythropoiesis during ontogenetic development, the author studied syntheses of DNA, RNA and protein of erythroid cells in fetal liver, neonatal and adult bone marrows of rats. In the bone marrow of neonatal animals erythropoiesis was stimulated by the intraperitoneal injection of cyclic nucleotide with enhanced DNA, RNA and protein syntheses of erythroid cells. Enhancing effect of dibutyryl-c-AMP on the erythropoiesis decreased gradually with advance of neonatal days. Autoradiographic observations revealed that in erythoid cells isolated from fetal liver and neonatal bone marrows, DNA-, RNA- and protein-snythesis was markedly stimulated by incubating with cyclic nucleotide, but not in those from adult bone marrow. Discussion was made on the changes in the regulatory mechanism of erythropoiesis according to the transition of hematopoietic organs during development.