Cell-published research mapped a brain circuit in mice that links deep sleep to growth hormone release and uncovered a feedback loop that also helps regulate wakefulness.
Hypothalamic GHRH neurons and two somatostatin neuron types shifted activity across sleep stages, while rising growth hormone activated the locus coeruleus, a brainstem region tied to alertness and cognition.
Electrode recordings, light-based stimulation and circuit tracing let the team track repeated sleep-wake cycles, showing distinct hormone-control patterns in REM and non-REM sleep.
The finding helps explain why poor sleep can disrupt growth, muscle repair, fat and glucose metabolism, and may raise risks tied to obesity, diabetes and cardiovascular disease.
Researchers said the circuit could guide future therapies for sleep disorders and metabolic or neurodegenerative diseases, including Parkinson's and Alzheimer's.