Expression of adiponectin receptors in osteoblasts and regulation of bone metabolism by adiponectin both in vitro[30] and in vivo[31,32] in addition to increased adiponectin gene expression induced by ucOC could support the concept of an adiponectin-OC loop [3,29] and the increased ucOC delivery in response to hypoadiponectinemia. This evidence concerns the gene ADIPOQ and adiponectin deficiency.