Effects of estradiol on hematopoietic and marrow adherent cells of dogs.

Hematopoietic and marrow adherent cells were examined in 5 ovariohysterectomized dogs treated once with 1.5 mg of 17 beta-estradiol cyclopentylpropionate/kg of body weight. All dogs initially developed thrombocytopenia and neutrophilic leukocytosis, with megakaryocytopenia and an increased myeloid/erythroid ratio of the marrow. Later, 2 dogs became thrombocytopenic and neutropenic, with megakaryocytopenia, decreased myeloid/erythroid ratio, and increased concentration of plasma cells and mast cells in the marrow. The concentration of marrow granulocyte-macrophage colony-forming units (CFU-GM) was decreased at 2 and 3 weeks in all dogs after estradiol treatment. The concentration of marrow fibroblast CFU-F was decreased in all estradiol-treated dogs at 1 and 2 weeks. The ability of marrow adherent cells to support CFU-GM colony formation was unchanged in estradiol-treated dogs. Estradiol sulfate at final concentrations of 10(-8) to 10(-4)M did not affect the in vitro growth of CFU-GM and CFU-F, or the hematopoietic ability of marrow adherent cells from nontreated dogs.