Blockade of endogenous growth hormone-releasing hormone receptors dissociates nocturnal growth hormone secretion and slow-wave sleep.
Level 2 - randomized trial
Individual randomized crossover trial in humans.
PubMed 15538933 · doi:10.1530/eje.0.1510561
What was done
Healthy men aged 20 to 33 years received a 12-hour overnight intravenous infusion (21:00 to 09:00 h) of either a GHRH antagonist ((N-Ac-Tyr(1), D-Arg(2)) GHRH-29 (NH2)) or saline vehicle. Antagonist efficacy was tested with an intravenous GHRH bolus at 07:00 h followed by GH sampling until 09:00 h. Sleep architecture was monitored with a limited-montage polysomnography study from 23:00 to 07:00 h.
What was found
The GHRH antagonist reduced the GH response to exogenous GHRH by 93 ± 1.8% (P = 0.012) compared to control. Despite this suppression, the percentage of slow-wave sleep did not differ between the saline and antagonist conditions (P = 0.607), and other quantifiable sleep parameters remained unchanged.
Why it matters
While exogenous GHRH promotes slow-wave sleep, this study demonstrates that endogenous GHRH receptor activation is not required for normal slow-wave sleep generation, effectively dissociating nocturnal GH surges from slow-wave sleep mechanisms.
Limits
The total sample size is not reported in the abstract. The study included only young healthy adult males, evaluated a single antagonist dosage, and used a limited polysomnography montage rather than full standard multichannel recording.
Cited by
- supports Endogenous growth hormone secretion peaks at night.