Document Detail


Influence of head-down bed rest on the circadian rhythms of hormones and electrolytes involved in hydroelectrolytic regulation.
MedLine Citation:
PMID:  11513324     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated in six men the impact of a 17-day head-down bed rest (HDBR) on the circadian rhythms of the hormones and electrolytes involved in hydroelectrolytic regulation. This HDBR study was designed to mimic an actual spaceflight. Urine samples were collected at each voiding before, during and after HDBR. Urinary excretion of aldosterone, arginine vasopressin (AVP), cyclic guanosine monophosphate (cGMP), cortisol, electrolytes (Na+ and K+) and creatinine were determined. HDBR resulted in a significant reduction of body mass (P < 0.01) and of caloric intake [mean (SEM) 2,778 (37) kcal.24 h(-1) to 2,450 (36) kcal.24 h(-1), where 1 kcal.h(-1) = 1.163 J.s(-1); P< 0.01]. There was a significant increase in diastolic blood pressure [71.8 (0.7) mmHg vs 75.6 (0.91) mmHg], with no significant changes in either systolic blood pressure or heart rate. The nocturnal hormonal decrease of aldosterone was clearly evident only before and after HDBR, but the day/night difference did not appear during HDBR. The rhythm of K+ excretion was unchanged during HDBR, whereas for Na+ excretion, a large decrease was shown during the night as compared to the day. The circadian rhythm of cortisol persisted. These data suggest that exposure to a 17-day HDBR could induce an exaggeration of the amplitude of the Na+ rhythm and abolition of the aldosterone rhythm.
Authors:
C Millet; M A Custaud; A M Allevard; M Zaouali-Ajina; T H Monk; S B Arnaud; B Claustrat; C Gharib; G Gauquelin-Koch
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  European journal of applied physiology     Volume:  85     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2001 Jul 
Date Detail:
Created Date:  2001-08-21     Completed Date:  2002-01-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  74-81     Citation Subset:  IM; S    
Affiliation:
Laboratoire de Physiologie de l'Environnement (GIP Exercise and EA 645), Faculté de Médecine, Lyon Grange-Blanche, France.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aldosterone / urine*
Arginine Vasopressin / urine
Blood Pressure / physiology
Body Mass Index
Circadian Rhythm / physiology*
Creatinine / urine
Cyclic GMP / urine
Diuresis / physiology
Energy Intake / physiology
Head-Down Tilt
Heart Rate / physiology
Humans
Hydrocortisone / urine
Male
Middle Aged
Posture / physiology
Potassium / urine*
Sodium / urine*
Stress, Physiological / physiopathology
Water-Electrolyte Balance / physiology*
Chemical
Reg. No./Substance:
113-79-1/Arginine Vasopressin; 50-23-7/Hydrocortisone; 52-39-1/Aldosterone; 60-27-5/Creatinine; 7440-09-7/Potassium; 7440-23-5/Sodium; 7665-99-8/Cyclic GMP
Investigator
Investigator/Affiliation:
T H Monk / U Pittsburgh Med Ctr, PA; S B Arnaud / ARC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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