Adaptation of hemopoietic tissue resulting from estrone-induced osteosclerosis in mice.

Abstract

ABSTRACTThe redistribution of hemopoietic tissue resulting from estrone‐induced osteosclerosis in the mouse was studied. As the marrow was gradually replaced by bone, extramedullary hematopoiesis in the spleen increased at a rate sufficient to maintain hemopoietic homeostasis.The total numbers of colony forming units (CFU) in the tibia and spleen as well as the proportion of CFU in cycle was assessed. After five injections of estrone, tibial CFUs decreased to 2% of control values whereas splenic CFUs increased approximately nine‐fold. The proliferative capacity of the splenic CFU was also increased in the estrone‐treated animals. The increased numbers of splenic CFUs as well as the increased proliferative capacity of this compartment are probably related to the ability of extramedullary hematopoiesis in the spleen to compensate for a marrow that has been replaced by bone.