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

The physiological role of 11beta hydroxy-androstenedione (11betaOHA), a primary adrenal steroid, remains unknown. In the present study, we investigated the effect of 11betaOHA on bone metabolism in vitro and in vivo. Administration of 11betaOHA enhanced the clonal growth of marrow osteoprogenitor cells cultured from normal rats. In ovariectomized rats, 11betaOHA restored osteogenesis and increased the bone mineral density at both the metaphyseal 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 11betaOHA. In addition, 11betaOHA increased alkaline phosphatase activity in cultured osteoblastic cells (MC3T3-E1 and SaOS-2). The androgenic and anabolic effects of 11betaOHA were respectively estimated to be less than 1/100th and 1/10th-1/100th of those of testosterone, while the estrogenic action of 11betaOHA was also very weak. These findings suggest an influence of 11betaOHA on physiological bone metabolism and indicate that this steroid may be useful for stimulating of bone formation in the treatment of osteoporosis.