High aerobic capacities in the skeletal muscles of seals, sea lions and fur seals : adaptations to diving hypoxia? /
The purpose of this project was to assess the aerobic
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=736824091&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The purpose of this project was to assess the aerobic capacity and the role of intramuscular triglycerides in the skeletal muscles of pinnipeds. Samples of swimming and non- swimming muscles were collected from Steller sea lions (Eumetopiasiubatus), harbor seals (Phoca vitulina), and northern fur seals (Callorhinus ursinus) using a needle biopsy technique. Upon collection samples were either fixed in 2% glutaraldehyde or frozen in liquid nitrogen. The volume densities of mitochondria, myofibrils, and lipid droplets were determined by electron microscopy. The activities of citrate synthase (CS), 0-hydroxyacyl CoA dehydrogenase (HAD) and the concentration of myoglobin were determined by spectrophotometry. The swimming muscle of harbor seals had average total mitochondrial volume densities of 9.3% Vv(mt,f), citrate synthase activities of 41.6 umol/min/g wet mass muscle, HAD activities of 51.9 umol/min/g wet mass muscle and myoglobin concentrations of 37.7 mg/g wet mass muscle. The swimming muscle of the Steller sea lions and northern fur seals had average volume densities of mitochondria of 6.0% and 8.9% Vv(mt,f), citrate synthase activities of 26.6 and 39.3 umol/min/g wet mass muscle, HAD activities of 22.8 and 47.5 umol/min/g wet mass muscle and myoglobin concentrations of 29.6 and 22.6 mg/g wet mass muscle, respectively. These values were 1.1 to 2.3 times greater than the values obtained from the non-swimming muscles. The volume densities of lipid droplets in the swimming muscles were generally less than 1% for all three species, but were 10 to 37 times greater than those measured in comparably sized terrestrial mammals. The volume densities of mitochondria were found to be 1.7 to 2.0 times greater than those measured for the locomotory muscles of terrestrial mammals of comparable size. Contrary to earlier reports, the results of this study show that the skeletal muscles of pinnipeds have enhanced aerobic capacities and are metabolically adapted for the utilization of intramuscular hypoxic conditions of diving. |
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| Item Description: | Vita. "Major Subject: Wildlife and Fisheries Sciences". |
| Physical Description: | x, 92 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 60-72. |