title: Changes in activity of chicken medullary bone cell populations in relation to the egg-laying cycle.
abstract: Osteoblastic and osteoclastic activity was studied in avian medullary bone in vivo. During the active period of eggshell calcification, medullary bone active resorption surface increased ninefold. This correlated with a sevenfold increase in the percentage of active osteoclasts. Osteoblast activity is also increased during the active period, as demonstrated by a twofold increase in the active osteoblastic surface. These findings and our observation that the medullary bone volume remains the same (+/- 13%) whether the eggshell is being formed (active period) or not (inactive period) led to the conclusion that the activities of osteoblasts and osteoclasts rapidly return to balance.
mesh_terms: D000818:Animals; D001862:Bone Resorption; D002118:Calcium / Q000378:metabolism; D002645:Chickens / Q000378:metabolism / Q000502:physiology*; D004528:Egg Shell / Q000378:metabolism; D005260:Female; D005269:Femur / Q000166:cytology / Q000378:metabolism; D010006:Osteoblasts / Q000502:physiology*; D010010:Osteoclasts / Q000502:physiology*; D010012:Osteogenesis; D010058:Oviposition
chemical_list: D002118:Calcium