The sleep modulating effects of peptides after sleep deprivation

A bi-directional interaction exists between sleep electroencephalogram (EEG) and endocrine activity. A key role was shown for the reciprocal interaction between sleep promoting growth hormone releasing hormone (GHRH) and the sleep impairing corticotropin releasing hormone (CRH) in male subjects. The pulsatile administration of GHRH suggests an sexual dimorphism. Sleep deprivation (SD) is strongly promoting sleep by increasing slow wave sleep (SWS) and rapid eye movement sleep (REMS). We performed a sleep-endocrine study in controls to investigate sleep modulating influences of GHRH and CRH on gender and age after SD. After one night of adaptation in 42 normal subjects (age 19–69) sleep-EEG was recorded and hormone profiles of growth hormone (GH), cortisol and renin were collected simultaneously. This baseline night was followed by 40 hours of SD. In the recovery night sleep-endocrine activity was retest and the subjects received between 2200 and 0100 hourly bolus injections of either placebo (PL), 50 ug CRH or 50 ug GHRH according to a randomised schedule. Sleep efficiency index (SEI), SWS, REMS and Non-REMS increased and wakefulness decreased after SD in each of the 3 treatments. The effect of GHRH on SEI and wakefulness was more distinct than after PL. The increase of REMS was highest after GHRH and lowest after CRH and SWS was more enhanced in women than in men. Our data suggest that GHRH augments sleep promotion after SD. In females CRH appears to enhance SWS.