Document Detail

Fuel homeostasis in the harbor seal during submerged swimming.
MedLine Citation:
PMID:  2045543     Owner:  NLM     Status:  MEDLINE    
1. The turnover rates and oxidation rates of plasma glucose, lactate, and free fatty acids (FFA) were measured in three harbor seals (average mass = 40 kg) at rest or during voluntary submerged swimming in a water flume at 35% (1.3 m.s-1) and 50% (2 m.s-1) of maximum oxygen consumption (MO2max). 2. For seals resting in water, the total turnover rates for glucose, lactate, and FFA were 23.2, 26.2, and 7.5, respectively. Direct oxidation of these metabolites accounted for approximately 7%, 27%, and 33% of their turnover and 3%, 7%, and 18% of the total ATP production, respectively. 3. For swimming seals, MO2max was achieved at a drag load equivalent to a speed of 3 m.s-1 and averaged 1.85 mmol, which is 9-fold greater than resting metabolism in water at 18 degrees C. 4. At 35% and 50% MO2max, glucose turnover and oxidation rates did not change from resting levels. Glucose oxidation contributed about 1% of the total ATP production during swimming. 5. At 50% MO2max, lactate turnover and anaerobic ATP production doubled, but the steady state plasma lactate concentration remained low at 1.1 mM. Lactate oxidation increased 63% but still contributed only 4% of the total ATP production. Anaerobic metabolism contributed about 1% of the total ATP production at rest and during swimming. 6. The plasma FFA concentration and turnover rate increased only 24% and 37% over resting levels, respectively, at 50% MO2max. However, the oxidation rate increased almost 3.5-fold and accounted for 85% of the turnover.(ABSTRACT TRUNCATED AT 250 WORDS)
R W Davis; M A Castellini; T M Williams; G L Kooyman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  160     ISSN:  0174-1578     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  1991  
Date Detail:
Created Date:  1991-07-15     Completed Date:  1991-07-15     Revised Date:  2009-06-08    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  627-35     Citation Subset:  IM; S    
Physiological Research Laboratory, Scripps Institution of Oceanography, La Jolla, CA 92037.
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MeSH Terms
Adenosine Triphosphate / biosynthesis
Blood Glucose / metabolism
Energy Metabolism*
Fatty Acids, Nonesterified / blood
Immersion / physiopathology
Lactates / blood
Lactic Acid
Oxygen Consumption
Seals, Earless / metabolism*
Grant Support
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Lactates; 50-21-5/Lactic Acid; 56-65-5/Adenosine Triphosphate

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