CSF-1, IGF-1, and the control of postnatal growth and development.

Growth hormone controls somatic growth in mammals by regulating the production of IGF-1, which is predominantly made by the liver. The development of cells within the MPS is controlled by the lineage-specific growth factor M-CSF (CSF-1). In this review, we summarize the role of CSF-1-dependent macrophages in somatic growth and organogenesis. We propose that macrophages are the major extrahepatic source of IGF-1 and that a surge of CSF-1 production contributes to the control of postnatal growth and organ maturation. Accordingly, CSF-1 may be considered a part of the GH/IGF-1 axis.