Document Detail


Hypoxic stimulus alters hypothalamic AMP-activated protein kinase phosphorylation concomitant to hypophagia.
MedLine Citation:
PMID:  17332269     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Acute exposure to hypobaric hypoxia is known to decrease food intake, but the molecular mechanisms of such alteration in feeding behavior remain unknown. We tested the hypothesis that hypothalamic AMP-activated protein kinase (AMPK) phosphorylation is affected by acute exposure to hypobaric hypoxia and thus would be involved in initial anorexia. To address this issue, male rats weighing 255-270 g were either submitted to hypobaric hypoxia (H, equivalent altitude of 5,500 m), maintained under local barometric pressure conditions (N), or pair-fed an equivalent quantity of food to that consumed by H rats (PF), for 6, 24, or 48 h. Daily food intake dropped by 73% during the first day of hypoxia (P<0.01) and remained by 46% lower than in N rats thereafter (P<0.01). Hypoxia per se, as estimated by comparing experimental data between the H and PF groups, increased ob gene transcription and plasma leptin concentration. A transient increase in glucose availability occurred in the H group compared with PF animals (P<0.05). The hypoxic stimulus led to an early and transient decrease in hypothalamic AMPK and acetyl-CoA carboxylase (ACC) phosphorylation, concomitant with hypophagia and associated alterations in nutrients and hormones. An increase in NPY mRNA levels occurred from day 1, similarly in H and PF rats, and thus mainly related to food restriction alone (P<0.05). In conclusion, the present study demonstrates that hypoxia per se inhibited AMPK and ACC phosphorylation in the hypothalamus, concomitant with profound anorexia. A powerful counterregulation occurs rapidly, mediated by NPY and devoted to avoid prolonged anorexia.
Authors:
N Simler; A Malgoyre; N Koulmann; A Alonso; A Peinnequin; A X Bigard
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Publication Detail:
Type:  Journal Article     Date:  2007-03-01
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  102     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-06-06     Completed Date:  2007-11-05     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2135-41     Citation Subset:  IM    
Affiliation:
CRSSA, Department of Human Factors, BP 87, 38702 La Tronche Cedex, France.
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MeSH Terms
Descriptor/Qualifier:
AMP-Activated Protein Kinases
Adaptation, Physiological
Animals
Anoxia / complications*,  physiopathology*
Eating Disorders / physiopathology*
Feeding Behavior*
Hypothalamus / enzymology*
Male
Multienzyme Complexes / metabolism*
Phosphorylation
Protein-Serine-Threonine Kinases / metabolism*
Rats
Rats, Wistar
Chemical
Reg. No./Substance:
0/Multienzyme Complexes; EC 2.7.11.1/AMP-Activated Protein Kinases; EC 2.7.11.1/Protein-Serine-Threonine Kinases

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


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