|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Medicine, University of Rochester, Rochester, NY, USA; Pharmacology & Physiology, University of Rochester, Rochester, NY, USA
2 Medicine, University of Rochester, Rochester, NY, USA
3 Neurology, University of Rochester, Rochester, NY, USA
* To whom correspondence should be addressed. E-mail: stephen_welle{at}urmc.rochester.edu.
Muscle concentrations of mRNAs encoded by mitochondrial DNA (mtDNA) decline with aging. To determine if this can be explained by diminished mtDNA levels, we measured the relative concentrations of mtDNA and a representative mtDNA transcript (encoding cytochrome c oxidase, subunit 2, COX2) in muscle of young (21-27 yr) and older subjects (65-75 yr). The amount of COX2 mRNA (relative to 28S rRNA) was 22% lower (P = 0.04) in older muscle, and the amount of mtDNA (relative to nuclear DNA) was 38% lower (P = 0.0002). The average level of mitochondrial transcription factor A (Tfam), a protein essential for mtDNA replication, was similar in younger and older muscle. Tfam mRNA, nuclear respiratory factor-1 mRNA, and several mRNAs encoding proteins required for mtDNA replication were expressed at similar levels in younger and older muscle. The mtDNA concentrations were only weakly related to age-adjusted aerobic fitness (VO2max) and self-reported physical activity levels. We conclude that the lower concentration of mitochondrial mRNAs in older muscle can be explained by a reduced concentration of mtDNA.
This article has been cited by other articles:
![]() |
J. E. Galgani, C. Moro, and E. Ravussin Metabolic flexibility and insulin resistance Am J Physiol Endocrinol Metab, November 1, 2008; 295(5): E1009 - E1017. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. G. Giannoulis, N. Jackson, F. Shojaee-Moradie, K. S. Nair, P. H. Sonksen, F. C. Martin, and A. M. Umpleby The Effects of Growth Hormone and/or Testosterone on Whole Body Protein Kinetics and Skeletal Muscle Gene Expression in Healthy Elderly Men: A Randomized Controlled Trial J. Clin. Endocrinol. Metab., August 1, 2008; 93(8): 3066 - 3074. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. E. Durham, D. T. Brown, D. M. Turnbull, and P. F. Chinnery Progressive depletion of mtDNA in mitochondrial myopathy Neurology, August 8, 2006; 67(3): 502 - 504. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. R. Short, M. L. Bigelow, J. Kahl, R. Singh, J. Coenen-Schimke, S. Raghavakaimal, and K. S. Nair From the Cover: Decline in skeletal muscle mitochondrial function with aging in humans PNAS, April 12, 2005; 102(15): 5618 - 5623. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Hagen, D. J. Krause, D. J. Baker, M. H. Fu, M. A. Tarnopolsky, and R. T. Hepple Skeletal Muscle Aging in F344BN F1-Hybrid Rats: I. Mitochondrial Dysfunction Contributes to the Age-Associated Reduction in VO2max J. Gerontol. A Biol. Sci. Med. Sci., November 1, 2004; 59(11): 1099 - 1110. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |