Department of Muscle Physiology, Faculty of Rehabilitation, University School of Physical Education, Krakow, Poland.
J Strength Cond Res. 2012 Dec;26(12):3262-9. doi: 10.1519/JSC.0b013e31827361d7.
Gonadal hormones and anabolic-catabolic hormone balance have potent influence on skeletal muscle tissue, but little is known about their action with regard to myosin heavy chain (MHC) transformation in humans. We investigated the relationship between skeletal muscle MHC isoform content in the vastus lateralis muscle and basal testosterone (T) concentration in 3 groups of subjects: endurance trained (E), sprint/strength trained (S), and untrained (U) young men. We have also determined basal sex hormone-binding globulin and cortisol (C) concentrations in untrained subjects to examine the relationship between MHC composition and the anabolic-catabolic hormone balance. Moreover, basal free testosterone (fT) and bioavailable testosterone (bio-T) concentrations were calculated for this subgroup. Despite significant differences in MHC isoform content (69.4 ± 2.39%, 61.4 ± 8.04%, and 37.5 ± 13.80% of MHC-2 for groups S, U, and E, respectively, Kruskal-Wallis: H = 18.58, p < 0.001), the T concentration was similar in the three groups of subjects (18.84 ± 5.73 nmol·L(-1), 18.60 ± 5.73 nmol·L(-1), and 20.73 ± 4.06 nmol·L(-1) for U, E, and S groups, respectively, Kruskal-Wallis: H = 1.11, p > 0.5). We have also found that in the U group, type 2 MHC in the vastus lateralis muscle is positively correlated with basal fT:C ratio (r = 0.63, p = 0.01). It is concluded that the differences in the training history and training specificity can be distinguished with regard to the MHC composition but not with regard to the basal T concentration. Simultaneously, it has been shown that MHC isoform content in human vastus lateralis muscle may be related to basal anabolic-catabolic hormone balance, and this hypothesis needs further investigation.
性腺激素和合成代谢-分解代谢激素平衡对骨骼肌组织有很强的影响，但对于人类的肌球蛋白重链 (MHC) 转化，它们的作用知之甚少。我们研究了 3 组年轻男性（耐力训练组 E、速度/力量训练组 S 和未训练组 U）股外侧肌的 MHC 同工型含量与基础睾酮 (T) 浓度之间的关系。我们还确定了未训练受试者的基础性激素结合球蛋白和皮质醇 (C) 浓度，以研究 MHC 组成与合成代谢-分解代谢激素平衡之间的关系。此外，还为该亚组计算了基础游离睾酮 (fT) 和生物可利用睾酮 (bio-T) 浓度。尽管 MHC 同工型含量存在显著差异（S、U 和 E 组分别为 69.4 ± 2.39%、61.4 ± 8.04%和 37.5 ± 13.80%的 MHC-2，Kruskal-Wallis：H = 18.58，p < 0.001），但三组受试者的 T 浓度相似（U、E 和 S 组分别为 18.84 ± 5.73 nmol·L(-1)、18.60 ± 5.73 nmol·L(-1)和 20.73 ± 4.06 nmol·L(-1)，Kruskal-Wallis：H = 1.11，p > 0.5）。我们还发现，在 U 组中，股外侧肌的 2 型 MHC 与基础 fT:C 比值呈正相关（r = 0.63，p = 0.01）。结论是，训练史和训练特异性的差异可以通过 MHC 组成来区分，但不能通过基础 T 浓度来区分。同时，已经表明，人类股外侧肌的 MHC 同工型含量可能与基础合成代谢-分解代谢激素平衡有关，这一假设需要进一步研究。
