| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Division of Endocrinology, Mayo Clinic, Rochester, Minnesota, USA
1Correspondence: Division of Endocrinology, Mayo Clinic, 200 1st St. SW, 5-194 Joseph, Rochester, MN 55905, USA. E-mail: nair.sree{at}mayo.edu
We investigated age and sex effects and determined whether androgen replacement in elderly individuals (
60 yr) could augment protein synthesis. Thirty young men and 32 young women (18–31 yr) were studied once, whereas 87 elderly men were studied before and after 1 yr of treatment with 5 mg/day testosterone (T), 75 mg/day dehydroepiandrosterone (DHEA), or placebo (P); and 57 elderly women were studied before and after 1 yr of treatment with 50 mg/day DHEA or P. [15N]Phenylalanine and [2H4]tyrosine tracers were infused, with measurements in plasma and vastus lateralis muscle. Whole-body protein synthesis per fat-free mass and muscle protein fractional synthesis rate (FSR) were lower in elderly than in young individuals (P<0.001), not significantly affected by hormone treatments, and higher in women than in men (P<0.0001), with no sex x age interaction. In regression analyses, peak O2 consumption (VO2peak), resting energy expenditure (REE), and sex were independently associated with muscle FSR, as were VO2peak, REE, and interactions of sex with insulin-like growth factor-II and insulin for whole-body protein synthesis. Women maintain higher protein synthesis than men across the lifespan as rates decline in both sexes, and neither full replacement of DHEA (in elderly men and women) nor partial replacement of bioavailable T (in elderly men) is able to amend the age-related declines.—Henderson, G. C., Dhatariya, K., Ford, G. C., Klaus, K. A., Basu, R., Rizza, R. A., Jensen, M. D., Khosla, S., O'Brien, P., Nair, K. S. Higher muscle protein synthesis in women than men across the lifespan, and failure of androgen administration to amend age-related decrements.
Key Words: proteolysis • remodeling • aging • sexual dimorphism
This article has been cited by other articles:
|
|
 |
|
  M. Srinivasan, B. A. Irving, R. L. Frye, P. O'Brien, S. J. Hartman, J. P. McConnell, and K. S. Nair Effects on Lipoprotein Particles of Long-Term Dehydroepiandrosterone in Elderly Men and Women and Testosterone in Elderly Men J. Clin. Endocrinol. Metab., April 1, 2010; 95(4): 1617 - 1625. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. I. Smith, D. T. Villareal, C. P. Lambert, D. N. Reeds, B. S. Mohammed, and B. Mittendorfer Timing of the initial muscle biopsy does not affect the measured muscle protein fractional synthesis rate during basal, postabsorptive conditions J Appl Physiol, February 1, 2010; 108(2): 363 - 368. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. I. Smith, P. Atherton, D. N. Reeds, B. S. Mohammed, H. Jaffery, D. Rankin, M. J. Rennie, and B. Mittendorfer No major sex differences in muscle protein synthesis rates in the postabsorptive state and during hyperinsulinemia-hyperaminoacidemia in middle-aged adults J Appl Physiol, October 1, 2009; 107(4): 1308 - 1315. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Kumar, P. Atherton, K. Smith, and M. J. Rennie Human muscle protein synthesis and breakdown during and after exercise J Appl Physiol, June 1, 2009; 106(6): 2026 - 2039. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. C. Henderson, B. A. Irving, and K. S. Nair Potential Application of Essential Amino Acid Supplementation to Treat Sarcopenia in Elderly People J. Clin. Endocrinol. Metab., May 1, 2009; 94(5): 1524 - 1526. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
