Document Detail


Impaired control of respiration in iron-deficient muscle mitochondria.
MedLine Citation:
PMID:  2610248     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Dietary iron deficiency (ID) decreases iron-containing proteins and hence respiratory capacity of skeletal muscle mitochondria (SMM), but noniron components are much less affected. Using a hexokinase plus glucose ATP-utilizing system, we studied control of respiration in isolated SMM from rats of variable iron status: ID, ID 3 days after intraperitoneal treatment with iron dextran, and control. We found that sensitivity of respiratory control (e.g., ATP/ADP at a given oxygen consumption) was positively related to state 3 respiratory capacity. Titration studies with carboxyatractyloside, a noncompetitive inhibitor of adenine nucleotide translocase (AdNT), revealed that AdNT concentration was unaffected by iron status. However, the turnover number of AdNT was markedly reduced by ID and improved with iron treatment. We conclude that in ID SMM, decreased maximal respiratory capacity is paralleled by impaired sensitivity to putative controllers of oxidative phosphorylation at any respiratory rate, despite normal levels of AdNT. A second study was designed to determine possible consequences of impaired sensitivity of respiratory control on motor unit recruitment during exercise. ID and normal rats were subjected to a program of walking treadmill exercise. Although exercise failed to induce any changes in oxidative enzyme levels in control rat, ID animals and exhibited substantial mitochondrial enzyme adaptation in hindlimb skeletal muscle. Furthermore, the most consistent enzymatic changes were observed to occur in fast glycolytic muscle fibers. These results suggest marked alterations in the pattern of muscle fiber recruitment during mild exercise in ID rodents and support the hypothesis that sensitivity of respiratory control in SMM is an important determinant of motor unit recruitment during aerobic exercise.
Authors:
W T Willis; P R Dallman
Related Documents :
1761288 - Impedance analysis applicable to cardiac muscle and smooth muscle bundles.
8734558 - Directional changes in neutrophil adherence following passive resting versus active ima...
22879018 - Nirs measurements with elite speed skaters: comparison between the ice rink and the lab...
17431308 - Toxicity and carcinogenicity mechanisms of fibrous antigorite.
10971258 - Right ventricular assist system feedback flow control parameter for a rotary blood pump.
10403868 - The use of breathing system filters as oxygen-delivery devices.
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  257     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Dec 
Date Detail:
Created Date:  1990-02-12     Completed Date:  1990-02-12     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  C1080-5     Citation Subset:  IM    
Affiliation:
Department of Pediatrics, School of Medicine, University of California, San Francisco 94143.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adenosine Diphosphate / metabolism
Adenosine Triphosphate / metabolism
Animals
Female
Iron / deficiency*,  pharmacology
Kinetics
Mitochondria, Muscle / drug effects,  metabolism*
Mitochondrial ADP, ATP Translocases / metabolism
Oxygen Consumption* / drug effects
Physical Exertion
Rats
Rats, Inbred Strains
Reference Values
Grant Support
ID/Acronym/Agency:
DK-13897/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
56-65-5/Adenosine Triphosphate; 58-64-0/Adenosine Diphosphate; 7439-89-6/Iron; 9068-80-8/Mitochondrial ADP, ATP Translocases

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


Previous Document:  Effects of cysteine protease inhibitors on rabbit cathepsin D maturation.
Next Document:  Delayed K+ current and external K+ in single cardiac Purkinje cells.