title: The effects of continuous estradiol therapy on cortical bone remodeling activity in the spayed beagle.
abstract: Ribs from 6 oophorectomized and 4 17 beta-estradiol-supplemented spayed, 4-year-old Beagle dams were subjected to histomorphometric analyses to determine what effects continuous estradiol treatment of 9 months duration had on the Basic Multicellular Unit (BMU) of cortical bone remodeling. The findings of this study suggest that 17 beta-estradiol has a two-step mode of action. First, this estrogen directly suppresses the formation of new BMUs. Secondly, it causes uncoupling of the Resorption/Formation (R/F) mechanism within each BMU, together with the creation of an approximate 1:1 balance between bone resorption and bone formation. This balance is probably responsible for the preservation of cortical bone mass seen to occur with continuous estrogen replacement therapy.
mesh_terms: D000818:Animals; D001846:Bone Development / Q000187:drug effects*; D001862:Bone Resorption / Q000187:drug effects; D001842:Bone and Bones / Q000033:anatomy & histology*; D004285:Dogs; D004958:Estradiol / Q000627:therapeutic use*; D005260:Female; D010052:Ovariectomy; D012272:Ribs / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology
chemical_list: D004958:Estradiol