High aerobic capacities in the skeletal muscles of pinnipeds: adaptations to diving hypoxia

1  Department of Medicine, University of California at San Diego, La Jolla, California, 92092-0623A; 2  Department of Wildlife and Fisheries Science, Texas A & M University, College Station, Texas 77845; and 3  Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0...

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Bibliographic Details
Published in:Journal of applied physiology (1985) 1999-04, Vol.86 (4), p.1247-1256
Main Authors: Kanatous, Shane B, DiMichele, Leonard V, Cowan, Daniel F, Davis, Randall W
Format: Article
Language:English
Subjects:
3-Hydroxyacyl CoA Dehydrogenases - metabolism
Adaptation, Physiological
Animals
Applied physiology
Biological and medical sciences
Body Weight
Citrate (si)-Synthase - metabolism
Diving - physiology
Enzymes
Female
Human physiology applied to population studies and life conditions. Human ecophysiology
Hypoxia - etiology
Hypoxia - physiopathology
Marine mammals
Medical sciences
Muscle, Skeletal - anatomy & histology
Muscle, Skeletal - physiology
Muscular system
Seals, Earless - anatomy & histology
Seals, Earless - physiology
Sigmodontinae
Species Specificity
Swimming - physiology
Transports. Aerospace. Diving. Altitude
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Summary:1  Department of Medicine, University of California at San Diego, La Jolla, California, 92092-0623A; 2  Department of Wildlife and Fisheries Science, Texas A & M University, College Station, Texas 77845; and 3  Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0588 The objective was to assess the aerobic capacity of skeletal muscles in pinnipeds. Samples of swimming and nonswimming muscles were collected from Steller sea lions ( Eumetopias jubatus , n  =   27), Northern fur seals ( Callorhinus ursinus , n  = 5), and harbor seals ( Phoca vitulina , n  = 37) by using a needle biopsy technique. Samples were either immediately fixed in 2% glutaraldehyde or frozen in liquid nitrogen. The volume density of mitochondria, myoglobin concentration, citrate synthase activity, and -hydroxyacyl-CoA dehydrogenase was determined for all samples. The swimming muscles of seals had an average total mitochondrial volume density per volume of fiber of 9.7%. The swimming muscles of sea lions and fur seals had average mitochondrial volume densities of 6.2 and 8.8%, respectively. These values were 1.7- to 2.0-fold greater than in the nonswimming muscles. Myoglobin concentration, citrate synthase activity, and -hydroxyacyl-CoA dehydrogenase were 1.1-   to 2.3-fold greater in the swimming vs. nonswimming muscles. The swimming muscles of pinnipeds appear to be adapted for aerobic lipid metabolism under the hypoxic conditions that occur during diving. mitochondria; citrate synthase; -hydroxyacyl-coenzyme A dehydrogenase; myoglobin
ISSN:8750-7587
1522-1601
DOI:10.1152/jappl.1999.86.4.1247