The increased bone mass in ΔFosB transgenic mice is independent of circulating leptin levels

Abstract

Transgenic mice overexpressing ΔFosB, a naturally occurring splice variant of FosB, develop an osteosclerotic phenotype. The increased bone formation has been shown to be due, at least in part, to autonomous effects of ΔFosB isoforms on cells of the osteoblast lineage. However, abdominal fat and marrow adipocytes are also markedly decreased in ΔFosB mice, leading to low serum leptin levels. Increased bone mass has been linked to the absence of leptin and leptin receptor signaling in ob/ob and db/db mice. Thus, in addition to affecting directly osteoblastogenesis and bone formation, ΔFosB isoforms might increase bone mass indirectly via a decrease in leptin. To test this hypothesis, we restor..