http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
High aerobic capacities in the skeletal muscles of seals, sea lions and fur seals
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
"Major Subject: Wildlife and Fisheries Sciences".
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 60-72.