Myelopoiesis and Marrow Adherent Cells in Estradiol-Treated Mice

Myelopoiesis and marrow adherent cells were evaluated in C57Bl/6J mice at two and four weeks after treatment with 0.1 mg 17 beta-estradiol cyclopentylpropionate. Estradiol-treated mice were lymphopenic and eosinopenic at two and four weeks; in addition, neutropenia occurred at four weeks. Numbers of lymphoid, granulocytic, and erythroid cells were decreased in the marrow at two and four weeks. The numbers of granulocyte-macrophage and fibroblast colony-forming units in the humeral marrow were also decreased at two and four weeks. However, the hematopoietic ability of marrow adherent cells was unchanged in estradiol-treated mice. Thymic cortical atrophy, metaphyseal osteosclerosis, and neutrophilic infiltration of the uterus occurred in estradiol-treated mice.