19617
document
Blockade of endogenous growth hormone-releasing hormone receptors dissociates nocturnal growth hormone secretion and slow-wave sleep . OBJECTIVES A temporal association between non-rapid eye movement ( NREM ) sleep stages 3 and 4 and nocturnal augmentation of GH release was found long ago , yet the precise mechanism for this association has not been identified . It has been shown , however that pulsatile GHRH administration increases both slow-wave sleep ( SWS ) and GH . Based on these data , a role for GHRH as an inducer of SWS was proposed . To test this hypothesis , we have performed the corollary experiment whereby the action of endogenous GHRH has been antagonized . DESIGN Healthy men ( 20-33 years old ) had an infusion of GHRH antagonist ( ( N-Ac-Tyr ( 1 ) , D-Arg ( 2 ) ) GHRH-29 ( NH ( 2 ) ) ) or saline for a 12-h period , between 2100 and 0900 h. An i.v . bolus of GHRH was given at 0700 h and GH samples were drawn from 0700 to 0900 h to document the efficacy of GH suppression by the GHRH antagonist . METHODS A limited montage sleep study was recorded from 2300 to 0700 h during each admission . Plasma GH concentrations were analyzed by the use of a sensitive chemiluminometric assay . RESULTS Effectiveness of the GHRH antagonist was validated in all subjects by demonstrating 93+/-1.8 % ( P=0.012 ) suppression of GH response to a GHRH bolus . Polysomnography demonstrated that the percentage of SWS was not different when saline and GHRH antagonist nights were compared ( P=0.607 ) ; other quantifiable sleep parameters were also unchanged . CONCLUSIONS We conclude that endogenous GHRH is indispensable for the nocturnal augmentation of GH secretion , but that it is unlikely to participate in the genesis of SWS .
19618
Intervention_Pharmacological
infusion of GHRH antagonist ( ( N-Ac-Tyr ( 1 ) , D-Arg ( 2 ) ) GHRH-29 ( NH ( 2 ) ) )
19619
Intervention_Control
saline for a 12-h period
19620
Intervention_Pharmacological
GHRH
19621
Outcome_Physical
nocturnal growth hormone secretion
19622
Outcome_Physical
slow-wave sleep
19623
Outcome_Physical
slow-wave sleep ( SWS )
19624
Outcome_Physical
GH
19625
Outcome_Physical
GH
19626
Outcome_Physical
Plasma GH concentrations
19627
Outcome_Other
Effectiveness
19628
Outcome_Physical
suppression of GH response
19629
Outcome_Physical
SWS
19630
Outcome_Physical
sleep parameters
19631
Participant_Condition
Healthy men ( 20-33 years old )