M-CSF activates mTOR/PI3K/Akt pathway, and it has been shown that rapamycin blocks M-CSF and RANKL-induced osteoclastogenesis.28 Our study offers novel insights pointing to inhibition of frequency of osteoclast progenitor pool by rapamycin in Sf mice leading to amelioration of osteopenia. This evidence concerns the gene MTOR and Osteopenia.