As every bodybuilder knows, a deep, restful sleep boosts levels of growth hormone to build strong muscle and bone and burn fat. And as every teenager should know, they won’t reach their full height potential without adequate growth hormone from a full night’s sleep.
But why lack of sleep — in particular the early, deep phase called non-REM sleep — lowers levels of growth hormone has been a mystery.
In a study published in the current issue of the journal Cell, researchers from University of California, Berkeley, dissect the brain circuits in mice that control growth hormone release during sleep and report a novel feedback mechanism in the brain that keeps growth hormone levels finely balanced.
The findings provide a map for understanding how sleep and hormone regulation interact. The new feedback mechanism could open avenues for treating people with sleep disorders tied to metabolic conditions like diabetes, as well as degenerative diseases like Parkinson’s and Alzheimer’s.
“People know that growth hormone release is tightly related to sleep, but only through drawing blood and checking growth hormone levels during sleep,” said study first author Xinlu Ding, a postdoctoral fellow in UC Berkeley’s Department of Neuroscience and the Helen Wills Neuroscience Institute. “We’re actually directly recording neural activity in mice to see what’s going on. We are providing a basic circuit to work on in the future to develop different treatments.”