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NASA NTRS · 20040087924

Hormonal changes during 17 days of head-down bed-rest

Custaud, Marc-Antoine·Arnaud, Sara B.·Monk, Timothy H.·Claustrat, Bruno·Gharib, Claude·Gauquelin-Koch, Guillemette
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Abstract

We investigated in six men the impact of 17 days of head-down bed rest (HDBR) on the daily rhythms of the hormones involved in hydroelectrolytic regulation. This HDBR study was designed to mimic a real space flight. Urine samples were collected at each voiding before, during and after HDBR. Urinary excretion of Growth Hormone (GH), Cortisol, 6 Sulfatoxymelatonin, Normetadrenaline (NMN) and Metadrenaline (NM) was determined. A decrease in urinary cortisol excretion during the night of HDBR was noted. For GH, a rhythm was found before and during HDBR. The rhythm of melatonin, evaluated with the urine excretion of 6 Sulfatoxymelatonin (aMT6S), the main hepatic metabolite, persisted throughout the experiment without any modification to the level of phase. A decrease during the night was noted for normetadrenaline urinary derivates, but only during the HDBR.

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Non-NASA CenterNASA Center ARCNASA Discipline Regulatory PhysiologyHormones/urineSpace FlightMelatonin/analogs & derivatives/urineBed RestHead-Down Tilt/adverse effects/physiologySupport, U.S. Gov't, Non-P.H.SGrowth Hormone/urineDiuresis/physiologyCatecholamines/urineCircadian Rhythm/physiologyHumanHemodynamic Processes/physiologyHydrocortisone/urineSupport, Non-U.S. Gov'tBody Weight/physiologyMaleAdult

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Custaud, Marc-Antoine, Arnaud, Sara B., Monk, Timothy H., Claustrat, Bruno, Gharib, Claude, Gauquelin-Koch, Guillemette. 2003-01-17. Hormonal changes during 17 days of head-down bed-rest. https://ntrs.nasa.gov/citations/20040087924

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