|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
E-mail contact: hmaclean@unimelb.edu.au
To identify mechanisms of anabolic androgen action in muscle, we generated male and female genomic androgen receptor (AR) knockout (ARKO) mice, and characterized muscle mass, contractile function, and gene expression. Muscle mass is decreased in ARKO males, but normal in ARKO females. The levator ani muscle, which fails to develop in normal females, is also absent in ARKO males. Force production is decreased from fast-twitch ARKO male muscle, and slow-twitch muscle has increased fatigue resistance. Microarray analysis shows up-regulation of genes encoding slow-twitch muscle contractile proteins. Real-time PCR confirms that expression of genes encoding polyamine biosynthetic enzymes, ornithine decarboxylase (Odc1), and S-adenosylmethionine decarboxylase (Amd1), is reduced in ARKO muscle, suggesting androgens act through regulation of polyamine biosynthesis. Altered expression of regulators of myoblast progression from proliferation to terminal differentiation suggests androgens also promote muscle growth by maintaining myoblasts in the proliferate state and delaying differentiation (increased Cdkn1c and Igf2, decreased Itg1bp3). A similar pattern of gene expression is observed in orchidectomized male mice, during androgen withdrawal-dependent muscle atrophy. In conclusion, androgens are not required for peak muscle mass in females. In males, androgens act through the AR to regulate multiple gene pathways that control muscle mass, strength, and fatigue resistance.—MacLean, H. E., Maria Chiu, W. S., Notini, A. J., Axell, A.-M., Davey, R. A., McManus, J. F., Ma, C., Plant, D. R., Lynch, G. S., Zajac, J. D. Impaired skeletal muscle development and function in male, but not female, genomic androgen receptor knockout mice.
This article has been cited by other articles:
![]() |
Y. Wu, W. Zhao, J. Zhao, Y. Zhang, W. Qin, J. Pan, W. A. Bauman, R. D. Blitzer, and C. Cardozo REDD1 Is a Major Target of Testosterone Action in Preventing Dexamethasone-Induced Muscle Loss Endocrinology, March 1, 2010; 151(3): 1050 - 1059. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Pires-Oliveira, A. L. G. C. Maragno, L. T. Parreiras-e-Silva, T. Chiavegatti, M. D. Gomes, and R. O. Godinho Testosterone represses ubiquitin ligases atrogin-1 and Murf-1 expression in an androgen-sensitive rat skeletal muscle in vivo J Appl Physiol, February 1, 2010; 108(2): 266 - 273. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. A Gentile, P. V Nantermet, R. L Vogel, R. Phillips, D. Holder, P. Hodor, C. Cheng, H. Dai, L. P Freedman, and W. J Ray Androgen-mediated improvement of body composition and muscle function involves a novel early transcriptional program including IGF1, mechano growth factor, and induction of {beta}-catenin J. Mol. Endocrinol., January 1, 2010; 44(1): 55 - 73. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Klover, W. Chen, B.-M. Zhu, and L. Hennighausen Skeletal muscle growth and fiber composition in mice are regulated through the transcription factors STAT5a/b: linking growth hormone to the androgen receptor FASEB J, September 1, 2009; 23(9): 3140 - 3148. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. E. MacLean and D. J. Handelsman Unraveling Androgen Action in Muscle: Genetic Tools Probing Cellular Mechanisms Endocrinology, August 1, 2009; 150(8): 3437 - 3439. [Full Text] [PDF] |
||||
![]() |
J. Ophoff, K. Van Proeyen, F. Callewaert, K. De Gendt, K. De Bock, A. Vanden Bosch, G. Verhoeven, P. Hespel, and D. Vanderschueren Androgen Signaling in Myocytes Contributes to the Maintenance of Muscle Mass and Fiber Type Regulation But Not to Muscle Strength or Fatigue Endocrinology, August 1, 2009; 150(8): 3558 - 3566. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Brown, J. Ning, J. A. Ferreira, J. L. Bogener, and D. B. Lubahn Estrogen receptor-{alpha} and -{beta} and aromatase knockout effects on lower limb muscle mass and contractile function in female mice Am J Physiol Endocrinol Metab, April 1, 2009; 296(4): E854 - E861. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Cheng, K. Wang, L. D. Kellam, Y. S. Lee, C.-G. Liang, Z. Han, N. R. Mtango, and K. E. Latham Effects of Ooplasm Manipulation on DNA Methylation and Growth of Progeny in Mice Biol Reprod, March 1, 2009; 80(3): 464 - 472. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |