Sleep enhances nocturnal plasma ghrelin levels in healthy subjects

• Published in: American journal of physiology: endocrinology and metabolism Vol. 286; no. 6; pp. E963 - E967
• Main Authors: Dzaja, Andrea, Dalal, Mira A, Himmerich, Hubertus, Uhr, Manfred, Pollmacher, Thomas, Schuld, Andreas
• Format: Journal Article
• Language: English
• Published: United States 01.06.2004
• Subjects: Adult; Analysis of Variance; Circadian Rhythm - physiology; Ghrelin; Humans; Hydrocortisone - blood; Male; Peptide Hormones - blood; Sleep - physiology; Sleep Deprivation - physiopathology; Sleep, REM - physiology
• ISSN: 0193-1849; 1522-1555
• DOI: 10.1152/ajpendo.00527.2003

Max Planck Institute of Psychiatry, 80804 Munich, Germany Submitted 18 November 2003 ; accepted in final form 5 February 2004 Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor, has been shown to promote slow-wave sleep (SWS, non-REM sleep stages 3 and 4). Plasma levels of ghrelin are dependent on food intake and increase in sleeping subjects during the early part of the night. It is unknown whether sleep itself affects ghrelin levels or whether circadian networks are involved. Therefore, we studied the effect of sleep deprivation on nocturnal ghrelin secretion. In healthy male volunteers, plasma levels of ghrelin, cortisol, and human growth hormone (hGH) were measured during two experimental sessions of 24 h each: once when the subjects were allowed to sleep between 2300 and 0700 and once when they were kept awake throughout the night. During sleep, ghrelin levels increased during the early part of the night and decreased in the morning. This nocturnal increase was blunted during sleep deprivation, and ghrelin levels increased only slightly until the early morning. Ghrelin secretion during the first hours of sleep correlated positively with peak hGH concentrations. We conclude that the nocturnal increase in ghrelin levels is more likely to be caused by sleep-associated processes than by circadian influences. During the first hours of sleep, ghrelin might promote sleep-associated hGH secretion and contribute to the promotion of SWS. growth hormone; cortisol; circadian rhythm; slow-wave sleep; sleep deprivation Address for reprint requests and other correspondence: A. Schuld, Max Planck Institute of Psychiatry, Kraepelinstrasse 10, 80804 Munich, Germany (E-mail: schuld{at}mpipsykl.mpg.de ).