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This Article Full Text Full Text (PDF) All Versions of this Article: 107/5/1381    most recent 00590.2009v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Google Scholar Articles by Dieli-Conwright, C. M. Articles by Schroeder, E. T. PubMed PubMed Citation Articles by Dieli-Conwright, C. M. Articles by Schroeder, E. T.

Influence of hormone replacement therapy on eccentric exercise induced myogenic gene expression in postmenopausal women

¹Division of Biokinesiology and Physical Therapy, Clinical Exercise Research Center, ; ²Department of Biochemistry and Molecular Biology, USC/Norris Comprehensive Cancer Center, ; ³Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California

Submitted 2 August 2009 ; accepted in final form 13 August 2009

Hormone replacement therapy (HRT) is used in postmenopausal women to relieve symptoms of menopause and prevent osteoporosis. We sought to evaluate changes in mRNA expression of key myogenic factors in postmenopausal women taking and not taking HRT following a high-intensity eccentric resistance exercise. Fourteen postmenopausal women were studied and included 6 control women not using HRT (59 ± 4 years, 63 ± 17 kg) and 8 women using traditional HRT (59 ± 4 yr, 89 ± 24 kg). Both groups performed 10 sets of 10 maximal eccentric repetitions of single-leg extension on a Cybex dynamometer at 60°/s. Muscle biopsies of the vastus lateralis were obtained from the exercised leg at baseline and 4 h after the exercise bout. Gene expression was determined using RT-PCR for follistatin, forkhead box 3A (FOXO3A), muscle atrophy F-box (MAFbx), muscle ring finger-1 (MuRF-1), myogenic differentiation factor (MyoD), myogenin, myostatin, myogenic factor 5 (Myf5), and muscle regulatory factor 4 (MRF4). At rest, the HRT group expressed higher levels of MyoD, myogenin, Myf5, MRF4, and follistatin (P < 0.05). In response to eccentric exercise, follistatin, MyoD, myogenin, Myf5, and MRF4 were significantly increased (P 0.05) and FOXO3A, MAFbx, MuRF-1, and myostatin were significantly decreased in the control and HRT groups (P 0.05). Significantly greater changes in mRNA expression of follistatin, FOXO3A, MAFbx, MuRF-1, MyoD, myogenin, myostatin, Myf5, and MRF4 (p0.05) occurred in the HRT group than in the control group after exercise. These data suggest that postmenopausal women using HRT express higher myogenic regulatory factor gene expression, which may reflect an attempt to preserve muscle mass. Furthermore, postmenopausal women using HRT experienced a greater myogenic response to maximal eccentric exercise.

follistatin; myostatin; myogenic differentiation factor