NPY and postmenopausal osteoporosis: This result, along with the evidences that bone resorption activity is relatively or absolutely augmented during senile or postmenopausal osteoporosis[46, 47] and the contributory role of osteocyte NPY in aging‐ and OVX‐induced bone‐fat imbalance determined in our study, suggests that osteocyte NPY can be released from the bone matrix to the bone marrow cavity during skeletal aging and menopause, which finally switches BMSC differentiation fate and induces bone‐fat imbalance.