Brain’s Delicate Balancing Act: new Insights into Growth Hormone and Sleep
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A groundbreaking study has revealed a previously unknown feedback mechanism in the brain that precisely regulates growth hormone levels during sleep, possibly opening new avenues for treating sleep disorders and neurodegenerative diseases. Researchers from the University of California, Berkeley and Stanford University have pinpointed specific brain circuits responsible for this delicate balance, offering a deeper understanding of how sleep impacts metabolic health and cognitive function.
The Link Between Sleep and Growth hormone
Sleep is widely recognized for its role in tissue growth and metabolic regulation, largely due to the enhanced release of growth hormone (GH) during sleep. Though, the precise neural mechanisms underlying this process remained elusive – untill now. The research, published in May 2025 in the journal Cell, demonstrates how GH release, amplified during both rapid eye movement (REM) and non-REM (NREM) sleep, is governed by the activity of distinct neurons within the hypothalamus.
Unraveling the Hypothalamic Circuit
The study, led by Ding et al., identifies two key players: neurons expressing GH-releasing hormone (GHRH), which stimulate GH release, and neurons expressing somatostatin (SST), which suppress it. SST neurons in the arcuate nucleus inhibit nearby GHRH neurons,creating a delicate balance. This newfound understanding of the neural circuit controlling GH release has far-reaching implications.Dysregulation of the locus coeruleus is linked to a range of psychiatric and neurological disorders, including Parkinson’s and alzheimer’s diseases. “Understanding the neural circuit for growth hormone release could eventually point toward new hormonal therapies to improve sleep quality or restore normal growth hormone balance,” stated a senior researcher from the University of California, Berkeley. The team believes this circuit could be a target for novel therapies, potentially even utilizing experimental gene therapies to modulate specific cell types.
How the study Was Conducted
The researchers employed cutting-edge techniques, including inserting electrodes into the brains of mice and using light to stimulate hypothalamic neurons, to meticulously map the neuroendocrine circuit. The natural sleep-wake cycles of mice, characterized by short sleep periods throughout the day and night, provided ample opportunities to study GH changes.Using advanced circuit tracing, they were able to differentiate how GHRH and somatostatin operate during different sleep stages.
The delicate Balance of Sleep and Arousal
The study reveals a interesting paradox: while GH accumulation during sleep stimulates the locus coeruleus and promotes wakefulness, overexcitation of the locus coeruleus can paradoxically induce sleepiness. “This suggests that sleep and growth hormone form a tightly balanced system: too little sleep reduces growth hormone release, and too much growth hormone can in turn push the brain toward wakefulness,” explained another researcher from the University of California, Berkeley.
This intricate balance is essential not only for growth, repair, and metabolic health but also for cognitive function. “Growth hormone not only helps you build your muscle and bones and reduce your fat tissue,but may also have cognitive benefits,promoting your overall arousal level when you wake up,” added a researcher.
the team emphasizes that this research provides a foundational circuit for future therapeutic development. “We are providing a basic circuit to work on in the future to develop different treatments,” they stated.
Xinlu Ding et al. 2025. Neuroendocrine circuit for sleep-dependent growth hormone release. Cell 188 (18): 4968-4979; doi: 10.1016/j.cell.2025.05.039
