Inhibition of myelopoiesis by serum from dogs exposed to estrogen.
The mechanism of estrogen-induced myelotoxicosis is unknown, although evidence indicates that estrogen does not directly damage the bone marrow granulocyte-macrophage progenitor cells and that the thymus is a probable mediator of the bone marrow suppression. Estrogen-induced production of a myelopoiesis-inhibitory factor by canine thymic stromal cells in vitro has been observed. Then, presence of a myelopoiesis-inhibitory factor in canine serum was investigated immediately after estrogen administration in vivo. Maximal reduction in colony-forming units-granulocyte/macrophage growth by sera from individual dogs varied. Individual dog sensitivity to estrogen-induced myelotoxicosis is seen clinically, and the cause is unknown. This serum factor could have a role in the eventual bone marrow hypoplasia seen in estrogen-treated dogs and is possibly the same factor produced by cultured thymic stromal cells exposed to estrogen.
Farris
G M
GM
Department of Pathology and Parasitology, College of Veterinary Medicine and Biological Sciences, Colorado State University 80523.
Benjamin
S A
SA
D000818:Animals; D001855:Bone Marrow Diseases / Q000097:blood / Q000139:chemically induced / Q000662:veterinary*; D003114:Colony-Forming Units Assay; D004283:Dog Diseases / Q000097:blood* / Q000139:chemically induced; D004285:Dogs; D004906:Erythrocyte Count / Q000662:veterinary; D004958:Estradiol / Q000031:analogs & derivatives* / Q000633:toxicity; D005260:Female; D007958:Leukocyte Count / Q000662:veterinary; D008264:Macrophages / Q000187:drug effects; D008297:Male; D010976:Platelet Count / Q000662:veterinary
D004958:Estradiol; C007630:estradiol 17 beta-cypionate