Pharmaceutical compositions and methods of use in regulation of mammalian bone forming activities of SFRPs (secreted frizzled-related proteins) are disclosed. SFRPs are secreted receptors for Wnts that are important polypeptide growth factors that are known to regulate fundamental biological processes like tissue polarity, embryonic development and tumorigenesis. A SFRP was isolated in human osteoblast cells and identified as SFRP-1 (also known as SARP-2) and shown to be regulated by osteogenic agents in the HOB cells in a differentiation selective manner modulating the life of osteoblasts/preosteocytes.