This study shows that scavenger receptor type I knockout mice (Scarb1-/-) have high adrenocorticotropic hormone (ACTH) levels but are osteopenic. Bone differentiation of Scarb1-/- mesenchymal stem cells at normal ACTH concentrations is reduced. However, 0–10 nM ACTH increases, but 100–1000 nM ACTH reduces wild-type osteoblast differentiation. Therefore, ACTH and the high-density lipoprotein receptor Scarb1 play independent roles in osteoblast differentiation.
- Irina L. Tourkova
- Steven F. Dobrowolski
- Harry C. Blair
