TY - JOUR

T1 - The activity of satellite cells and myonuclei following 8 weeks of strength training in young men with suppressed testosterone levels

AU - Kvorning, T

AU - Kadi, F

AU - Schjerling, P.

AU - Andersen, M.

AU - Brixen, K.

AU - Suetta, C

AU - Madsen, K

N1 - © 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

PY - 2015/3

Y1 - 2015/3

N2 - AIM: To investigate how suppression of endogenous testosterone during an 8-week strength training period influences the activity of satellite cells and myonuclei.METHODS: Twenty-two moderately trained young men participated in this randomized, placebo-controlled, and double-blinded intervention study. The participants were randomized to treatment with a GnRH analogue, goserelin (n = 12), which suppresses testosterone or placebo (n = 10) for 12 weeks. The strength training period of 8 weeks started after 4 weeks of treatment and included exercises for all major muscles. Biopsies were obtained from the mid-portion of the vastus lateralis muscle.RESULTS: Testosterone resting level in goserelin was 10-20 times lower compared with placebo, and the training-induced increase in the level of testosterone was abolished in goserelin. Training increased satellite cells number in type II fibres by 20% in placebo and by 52% in goserelin (P < 0.01), whereas the myonuclear number significantly increased by 12% in type II fibres in placebo and remained unchanged in goserelin (P < 0.05). No changes in satellite cells and myonuclei were seen in type I fibres in either group. Data from the microarray analysis indicated that low testosterone affects the bone morphogenetic proteins signalling, which might regulate proliferation vs. differentiation of satellite cells.CONCLUSION: Eight weeks of strength training enhances the myonuclear number in type II fibres, and this is largely blocked by the suppression of testosterone. The data indicate that low testosterone levels could reduce the differentiation of satellite cells to myonuclei via the bone morphogenetic proteins signalling pathway, resulting in reduced increases in lean leg mass.

AB - AIM: To investigate how suppression of endogenous testosterone during an 8-week strength training period influences the activity of satellite cells and myonuclei.METHODS: Twenty-two moderately trained young men participated in this randomized, placebo-controlled, and double-blinded intervention study. The participants were randomized to treatment with a GnRH analogue, goserelin (n = 12), which suppresses testosterone or placebo (n = 10) for 12 weeks. The strength training period of 8 weeks started after 4 weeks of treatment and included exercises for all major muscles. Biopsies were obtained from the mid-portion of the vastus lateralis muscle.RESULTS: Testosterone resting level in goserelin was 10-20 times lower compared with placebo, and the training-induced increase in the level of testosterone was abolished in goserelin. Training increased satellite cells number in type II fibres by 20% in placebo and by 52% in goserelin (P < 0.01), whereas the myonuclear number significantly increased by 12% in type II fibres in placebo and remained unchanged in goserelin (P < 0.05). No changes in satellite cells and myonuclei were seen in type I fibres in either group. Data from the microarray analysis indicated that low testosterone affects the bone morphogenetic proteins signalling, which might regulate proliferation vs. differentiation of satellite cells.CONCLUSION: Eight weeks of strength training enhances the myonuclear number in type II fibres, and this is largely blocked by the suppression of testosterone. The data indicate that low testosterone levels could reduce the differentiation of satellite cells to myonuclei via the bone morphogenetic proteins signalling pathway, resulting in reduced increases in lean leg mass.

KW - Adult

KW - Age Factors

KW - Biopsy

KW - Double-Blind Method

KW - Gene Expression Profiling

KW - Gene Expression Regulation

KW - Goserelin

KW - Humans

KW - Male

KW - Muscle Fibers, Fast-Twitch

KW - Quadriceps Muscle

KW - RNA, Messenger

KW - Resistance Training

KW - Satellite Cells, Skeletal Muscle

KW - Sex Factors

KW - Testosterone

KW - Time Factors

KW - Young Adult

U2 - 10.1111/apha.12404

DO - 10.1111/apha.12404

M3 - Journal article

C2 - 25294097

VL - 213

SP - 676

EP - 687

JO - Acta Physiologica

JF - Acta Physiologica

SN - 1748-1708

IS - 3

ER -