A primary adrenal steroid, 11 beta-hydroxyandrostenedione, has an osteotropic effect and little androgenic activity

The physiological role of 11 beta hydroxy-androstenedione (11 beta OHA), a primary adrenal steroid, remains unknown. In the present study, we investig ated the effect of 11 beta OHA on bone metabolism in vitro and in vivo. Adm inistration of 11 beta OHA enhanced the clonal growth of marrow osteoprogen itor cells cultured from normal rats. In ovariectomized rats, 11 beta OHA r estored osteogesis and increased the bone mineral density at both the metap hyseal and diaphyseal regions of the femur. Bone histomorphometric study of ovariectomized rats demonstrated that the mineral apposition rate of both cortical bone and trabecular bone was increased by treatment with 11 beta O HA. In addition, 11 beta OHA increased alkaline phosphatase activity in cul tured osteoblastic cells (MC3T3-E1 and SaOS-2). The androgenic and anabolic effects of 11 beta OHA were respectively estimated to be less than 1/100th and 1/10th-1/100th of those of testosterone, while the estrogenic action o f 11 beta OHA was also very weak. These findings suggest an influence of 11 beta OHA on physiological bone metabolism and indicate that this steroid m ay be useful for stimulating of bone formation in the treatment of osteopor osis. (C) 2000 Elsevier Science Ltd. All rights reserved.