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United States Department of Agriculture

Agricultural Research Service

Research Project: BONE METABOLISM IN OBESITY

Location: Dietary Prevention of Obesity-related Disease Research

Title: Bone marrow oxytocin mediates the anabolic action of estrogen on the skeleton)

Author
item Colaianni, Graziana
item Sun, Li
item Di benedetto, Andriana
item Tamma, Roberto
item Zhu, Ling-ling
item Cao, Jay
item Grano, Maria
item Yuan, Tony
item Colucci, Sylva
item Cuscito, Concetta
item Mancini, Lucia
item Li, Jinhua
item Nishimori, Katsuhiko
item Bab, Itai
item Lee, Heon-jin
item Iqbal, Jameel
item Young, W. scott
item Rosen, Clifford
item Zallone, Alberta
item Zaidi, Mone

Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/18/2012
Publication Date: 8/17/2012
Publication URL: http://handle.nal.usda.gov/10113/58300
Citation: Colaianni, G., Sun, L., Di Benedetto, A., Tamma, R., Zhu, L., Cao, J.J., Grano, M., Yuan, T., Colucci, S., Cuscito, C., Mancini, L., Li, J., Nishimori, K., Bab, I., Lee, H., Iqbal, J., Young, W., Rosen, C., Zallone, A., Zaidi, M. 2012. Bone marrow oxytocin mediates the anabolic action of estrogen on the skeleton. Proceedings of the National Academy of Sciences. 287(34):29159-29167.

Interpretive Summary: Oxytocin (OT) is a nanopeptide synthesized in the hypothalamus and released into circulation by the posterior pituitary. Its primary function is to mediate the milk ejection reflex in nursing mammals1. It also augments uterine contraction during parturition2. Serum OT levels peak during late pregnancy and lactation. These periods correspond, respectively, to maximal fetal and post-natal bone growth, because of which, the mother must loose ~120g of calcium from her skeleton3,4. Hormonal adaptations, including low estrogen and elevated PTHrP levels, permit this maternal hyper-resorption and intergenerational calcium transfer5. However, it is surprising that shortly after these periods of profound bone loss, the mother’s skeleton is rapidly repleted; if not, pregnancy- and lactation-associated osteoporosis ensues. The mechanisms for this dramatic skeletal recovery remain poorly understood.

Technical Abstract: Estrogen withdrawal in women due to natural or artificial menopause is followed by rapid bone loss, osteoporosis, and a high fracture risk. Replacement with estrogen prevents this bone loss and reduces the risk of fracture. Estrogen uses two mechanisms to exert this effect: it inhibits bone resorption by osteoclasts and stimulates bone formation by osteoblasts. While the antiresorptive actions of estrogen arise from the inhibition of the MAP kinase JNK, the mechanism of its effect on the osteoblast remains unclear. Here we show that the osteoblast-directed anabolic action of estrogen occurs, at least in part, through an intermediary, oxytocin (OT), produced by bone marrow osteoblasts in response to estrogen.

Last Modified: 8/24/2016
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