Endocrine Abstracts

That gonadal failure triggers osteoporosis while obesity protects from it, this led us to hypothesize that there was a common endocrine control of bone mass, body weight and reproduction. In the first phase of this work we aimed at demonstrating that there was a control of bone mass by hormones regulating body weight and reproduction. We showed that the adipocyte-derived hormone leptin regulates bone mass following its binding to hypothalamic neurons and through the use of two distinct neural mediators, the sympathetic tone and CART (cocaine amphetamine regulated transcript). Both of these mediators act on osteoblast whose proliferation and function they regulate through distinct molecular pathways. More recently we asked the reverse question namely are osteoblast regulating energy metabolism? In other words in bone an endocrine organ? We will present at the meeting experimental evidence indicating that osteoblasts do regulate energy metabolism albeit in ways that we did not anticipate.