Influences of age and dietary restriction on gastrocnemius electron transport system activities in mice.
Alterations in the mitochondrial electron transport system (ETS) may contribute to aging. Dietary restriction (DR) provides a model to investigate retarded aging. ETS activities were measured in gastrocnemius from 10- and 20-month-old B6C3F1 female mice fed either ad libitum (AL) or DR diets (40% < AL). Older (26 month old) AL mice were studied for complex IV. Activities of complexes I, III, and IV decreased 54-74% from 10 to 20 months of age in AL mice. At 10 months, activities of complexes I, III, and IV were 33-64% lower in DR compared to AL mice. The Km for ubiquinol-2 of complex III increased 29% by 20 months of age in AL mice while no change occurred in DR mice. The Vmax of complex IV declined by 90% from 10 to 26 months of age in AL mice and this change was opposed by DR. Complex IV contains high- and low-affinity binding sites. The Km for high-affinity sites was not influenced by age or diet through 20 months; however, the Km was approximately twofold higher at 26 months in AL mice. The percentage of total binding sites which were of high affinity fell from 68% at 10 months in AL mice to 46% at 20 months and was even lower (33%) at 26 months. This value was 80% for DR mice at 10 and 20 months. These alterations with aging in mitochondrial ETS capacities may contribute to decreases in skeletal muscle function.
Desai
V G
VG
National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
Weindruch
R
R
Hart
R W
RW
Feuers
R J
RJ
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001665:Binding Sites; D004032:Diet; D004579:Electron Transport; D005260:Female; D005609:Free Radicals / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008931:Mitochondria, Muscle / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*
D000975:Antioxidants; D005609:Free Radicals; D009124:Muscle Proteins