Document Detail

The purine nucleotide cycle. Studies of ammonia production by skeletal muscle in situ and in perfused preparations.
MedLine Citation:
PMID:  873929     Owner:  NLM     Status:  MEDLINE    
Ammonia production by hind limbs of rat was studied in perfused preparations during rest, exercise, and hypoxia, and while the perfusate contained epinephrine or cyanide. Ammonia production by hind limbs was also studied in situ during rest and exercise. Strong correlations were observed between ammonia, IMP, and lactate formation. Adenylosuccinate was not present in detectable amounts in resting muscle (less than 1 nmol/g dry weight) but it appeared and rose sharply in exercising muscle, and then declined during recovery. The maximum found was about 18 nmol/g dry weight. When IMP accumulation exceeded 2.8 mumol/g dry weight, the formation of adenylosuccinate diminished, presumably because of an inhibition of adenylosuccinate synthetase by excess substrate. Exercise resulted in a greatly increased output of ammonia and a decreased output of alanine and glutamine. The tissue contents of aspartate and glutamate were decreased, while that of alanine was increased. The content of malate increased 3-fold during exercise. Epinephrine, hypoxia, and cyanide each caused an increased output of ammonia at the expense of the amino acid content of the tissue. These results provide evidence for the operation of the purine nucleotide cycle in skeletal muscle under various conditions that are associated with an increased rate of glycolysis.
M N Goodman; J M Lowenstein
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  252     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1977 Jul 
Date Detail:
Created Date:  1977-08-25     Completed Date:  1977-08-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  5054-60     Citation Subset:  IM; S    
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MeSH Terms
Adenosine Monophosphate / metabolism
Alanine / metabolism
Ammonia / biosynthesis*
Anoxia / metabolism
Citrates / metabolism
Cyanides / pharmacology
Epinephrine / pharmacology
Glutamine / metabolism
Hypoxanthines / metabolism
Inosine Nucleotides / metabolism
Malates / metabolism
Muscles / drug effects,  metabolism*
Physical Exertion
Purine Nucleotides / metabolism
Succinates / metabolism
Reg. No./Substance:
0/Citrates; 0/Cyanides; 0/Hypoxanthines; 0/Inosine Nucleotides; 0/Malates; 0/Purine Nucleotides; 0/Succinates; 51-43-4/Epinephrine; 56-41-7/Alanine; 56-85-9/Glutamine; 61-19-8/Adenosine Monophosphate; 7664-41-7/Ammonia

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

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