Bone serves primarily as a support for the entire body and is the primary regulator of calcium homeostasis and hematopoietic function.An increasing number of recent studies have highlighted the importance of bone as an endocrine organ.These studies suggest that bone-derived factors regulate local bone metabolism and the body's metabolic functions.These findings could help to provide novel pathologic mechanisms for associated metabolic diseases or may help to diagnose,treat,and prevent metabolic diseases such as osteoporosis,obesity,and diabetes.This review summarizes the regulatory effects of bone and bone-derived factors on energy metabolism and discusses future research directions.