Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, 35017 Las Palmas de Gran Canaria, Canary Island, Spain.
Eur J Appl Physiol. 2010 Mar;108(4):749-58. doi: 10.1007/s00421-009-1281-5.
In rodents, endurance training increases leptin sensitivity in skeletal muscle; however, little is known about the effects of exercise on the leptin signalling system in human skeletal muscle. Thus, to determine whether chronic muscle loading increases leptin receptor (OB-R170) protein expression, body composition dual-energy X-ray absorptiometry was assessed in nine professional male tennis players (24 +/- 4 years old) and muscle biopsies were obtained from the dominant (DTB) and non-dominant (NDTB) arm triceps brachii (TB), and also from the right vastus lateralis (VL). In each biopsy, the protein content of OB-R170, perilipin A, suppressor of cytokine signalling 3 (SOCS3), protein tyrosine phosphatase 1B (PTP1B) and signal transducer and activator of transcription 3 (STAT3) phosphorylation were determined by western blot. The DTB had 15% greater lean mass (P < 0.05) and 62% greater OB-R170 protein expression (P < 0.05) than the NDTB. SOCS3 and PTP1B protein expression was similar in both arms, while STAT3 phosphorylation was reduced in the NDTB. OB-R170 protein content was also higher in DTB than in VL (P < 0.05). In summary, this study shows that the functional isoform of the leptin receptor is up-regulated in the hypertrophied TB. The latter combined with the fact that both SOCS3 and PTP1B protein expression were unaltered is compatible with increased leptin sensitivity in this muscle. Our findings are also consistent with a role of leptin signalling in muscle hypertrophy in healthy humans.
在啮齿动物中，耐力训练会增加骨骼肌中的瘦素敏感性；然而，对于运动对人体骨骼肌中瘦素信号系统的影响知之甚少。因此，为了确定慢性肌肉负荷是否会增加瘦素受体（OB-R170）蛋白表达，我们评估了 9 名职业男性网球运动员（24 +/- 4 岁）的身体成分双能 X 射线吸收法，并从优势（DTB）和非优势（NDTB）手臂肱三头肌（TB）以及右股外侧肌（VL）获得肌肉活检。在每个活检中，通过 Western blot 测定 OB-R170、围脂素 A、细胞因子信号转导抑制因子 3（SOCS3）、蛋白酪氨酸磷酸酶 1B（PTP1B）和信号转导和转录激活因子 3（STAT3）磷酸化的蛋白含量。与 NDTB 相比，DTB 的瘦体重增加了 15%（P < 0.05），OB-R170 蛋白表达增加了 62%（P < 0.05）。两条手臂的 SOCS3 和 PTP1B 蛋白表达相似，而 NDTB 的 STAT3 磷酸化减少。与 VL 相比，DTB 的 OB-R170 蛋白含量也更高（P < 0.05）。总之，本研究表明，瘦素受体的功能性同工型在肥大的 TB 中上调。后一种情况加上 SOCS3 和 PTP1B 蛋白表达不变，与该肌肉中瘦素敏感性增加一致。我们的发现也与瘦素信号在健康人类肌肉肥大中的作用一致。
