Elevated endogenous testosterone concentrations potentiate muscle androgen receptor responses to resistance exercise.
The purpose of this study was to determine the influence of endogenous circulating testosterone (T) on muscle androgen receptor (AR) responses to acute resistance exercise (RE). Six healthy men (26+/-4 years; 176+/-5 cm; 75.8+/-11.4 kg) performed a knee extension exercise protocol on two occasions separated by 1-3 weeks. Rest preceded one trial (i.e., control [CON] trial) and a high-volume upper-body RE protocol designed to increase circulating T preceded the other trial (i.e., high T [HT] trial). Serial blood samples were obtained throughout each trial to determine circulating T concentrations. Biopsies of the vastus lateralis were obtained pre-RE (REST), 10-min post-RE (+10), and 180-min post-RE (+180) to determine muscle AR content. Circulating T concentrations remained stable during CON. Alternately, HT significantly (p< or =0.05) increased T concentrations above resting values (+16%). Testosterone area-under-the-time curve during HT exceeded CON by 14%. AR content remained stable from REST to +10 in both trials. Compared to the corresponding +10 value, muscle AR content at +180 tended to decrease during CON (-33%; p=0.10) but remained stable during HT (+40%; p=0.17). Muscle AR content at +180 during the HT trial exceeded the corresponding CON value. In conclusion, acute elevations in circulating T potentiated muscle AR content following RE.
Spiering
Barry A
BA
Department of Kinesiology, University of Connecticut, 2095 Hillside Road, Storrs, CT 06269, USA.
Kraemer
William J
WJ
Vingren
Jakob L
JL
Ratamess
Nicholas A
NA
Anderson
Jeffrey M
JM
Armstrong
Lawrence E
LE
Nindl
Bradley C
BC
Volek
Jeff S
JS
Häkkinen
Keijo
K
Maresh
Carl M
CM
D000328:Adult; D019540:Area Under Curve; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000378:metabolism; D011944:Receptors, Androgen / Q000032:analysis*; D012146:Rest; D013739:Testosterone / Q000097:blood*; D013997:Time Factors; D055815:Young Adult
C410798:AR protein, human; D011944:Receptors, Androgen; D013739:Testosterone