The expression of androgen-regulated genes before and after a resistance exercise bout in younger and older men

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Deutscher übersetzter Titel:Der Ausdruck androgen-gesteuerter Gene vor und nach einer Krafttrainingsbelastung bei jüngeren und älteren Männern
Autor:Roberts, Michael D.; Dalbo, Vincent J.; Hassell, Scott E.; Kerksick, Chad M.
Erschienen in:Journal of strength and conditioning research
Veröffentlicht:23 (2009), 4, S. 1060-1067, Lit.
Format: Literatur (SPOLIT)
Publikationstyp: Zeitschriftenartikel
Medienart: Gedruckte Ressource Elektronische Ressource (online)
Sprache:Englisch
ISSN:1064-8011, 1533-4287
DOI:10.1519/JSC.0b013e3181a59bdd
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Erfassungsnummer:PU200909004100
Quelle:BISp

Abstract des Autors

This cross-sectional study examined aging and resistance exercise-related changes in intramuscular gene expression in younger (21.3 ± 0.6 years, 84.8 ± 6.0 kg, 26.6 ± 2.1 kg[middle dot]m-2; n = 11) and older men (67.6 ± 1.3 years, 88.7 ± 4.8 kg, 28.6 ± 1.4 kg[middle dot]m-2; n = 13) surrounding a single bout of resistance exercise. Participants completed 3 x 10 repetitions at 80% of their 1 repetition maximum for Smith squat, leg press, and leg extension. Muscle biopsies were obtained before and 24 hours after exercise, whereas venous blood was collected before, immediately after and 24 hours after exercise. Free testosterone levels were greater in younger participants at all time points (p < 0.05), in addition to a greater increase in the younger men immediately post exercise (p < 0.01). Preexercise human growth hormone levels between age groups were similar (p > 0.05). Human growth hormone increased immediately post exercise in both groups (p < 0.05) with a greater response occurring in the younger (p < 0.001) men. Older men expressed greater levels of androgen receptor (AR) at rest (p = 0.02). A significant correlation existed between preexercise free testosterone levels basal AR gene expression (r = -0.59, p < 0.01). These data suggest that AR expression patterns may be related to circulating free testosterone levels. Although these findings do not fully unveil the genomic effects of androgen signaling and its relationship to muscle wasting conditions, these results provide a platform for future researchers seeking to employ gene therapy to remedy muscle loss. Verf.-Referat