Hunger, Hormones, and Bone Health

[Dean Pomerleau]

[Note: another one for the elusive "Non-CR Health & Longevity" Forum...]

 

All,

 

Here are highlights from an interesting new study [1] investigating the link between the activity of certain neurons in your hypothalamus (which are known to be involved in feeding and compulsive behavior) and bone health. To quote the authors:

 

"The less hungry you are, the lower your bone density, and surprisingly, the effects of these neurons on bone mass are independent of the effect of the hormone leptin on these same cells."

 

 I'm rarely hungry, but maybe hunger is good for us after all!

 

--Dean

 

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[1] AgRP Neurons Regulate Bone Mass

 

Jae Geun Kim, Ben-Hua Sun, Marcelo O. Dietrich, Marco Koch, Gang-Qing Yao, Sabrina Diano, Karl Insogna6, Tamas L. Horvath

 

DOI: http://dx.doi.org/10.1016/j.celrep.2015.08.070

The hypothalamus has been implicated in skeletal metabolism. Whether hunger-promoting neurons of the arcuate nucleus impact the bone is not known. We generated multiple lines of mice to affect AgRP neuronal circuit integrity. We found that mice with Ucp2 gene deletion, in which AgRP neuronal function was impaired, were osteopenic. This phenotype was rescued by cell-selective reactivation of Ucp2 in AgRP neurons. When the AgRP circuitry was impaired by early postnatal deletion of AgRP neurons or by cell autonomous deletion of Sirt1 (AgRP-Sirt1−/−), mice also developed reduced bone mass. No impact of leptin receptor deletion in AgRP neurons was found on bone homeostasis. Suppression of sympathetic tone in AgRP-Sirt1−/− mice reversed osteopenia in transgenic animals. Taken together, these observations establish a significant regulatory role for AgRP neurons in skeletal bone metabolism independent of leptin action.