The House of Sport, Team Danmark, Broendby, Denmark; Institute of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
Acta Physiol (Oxf). 2015 Mar;213(3):676-87. doi: 10.1111/apha.12404. Epub 2014 Nov 15.
To investigate how suppression of endogenous testosterone during an 8-week strength training period influences the activity of satellite cells and myonuclei.
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.
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.
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.
研究在 8 周力量训练期间抑制内源性睾酮如何影响卫星细胞和肌核的活性。
22 名中等训练水平的年轻男性参与了这项随机、安慰剂对照、双盲干预研究。参与者被随机分为接受 GnRH 类似物戈舍瑞林（n = 12）治疗组或安慰剂（n = 10）组，治疗期为 12 周，其中戈舍瑞林组可抑制睾酮的产生，而安慰剂组则无作用。8 周的力量训练期在治疗 4 周后开始，包括所有主要肌肉的运动。从股外侧肌中部取活检。
与安慰剂相比，戈舍瑞林组的睾酮基础水平低 10-20 倍，且训练引起的睾酮水平升高在戈舍瑞林组中被消除。与安慰剂组相比，训练使 II 型纤维中的卫星细胞数量增加了 20%，而在戈舍瑞林组中增加了 52%（P < 0.01），而 II 型纤维中的肌核数量则显著增加了 12%，而在戈舍瑞林组中则保持不变（P < 0.05）。两组的 I 型纤维中，卫星细胞和肌核均无变化。微阵列分析数据表明，低睾酮会影响骨形态发生蛋白信号通路，这可能会调节卫星细胞的增殖与分化。
8 周的力量训练可增强 II 型纤维中的肌核数量，而这一作用主要被睾酮的抑制所阻断。研究数据表明，低睾酮水平可能会通过骨形态发生蛋白信号通路减少卫星细胞向肌核的分化，从而导致瘦体重的增加减少。
