Department of Nutrition, Food and Exercise Science, Florida State University, Tallahassee, FL 32306, USA.
Institute of Sports Sciences and Medicine, Florida State University, Tallahassee, FL 32306, USA.
Appl Physiol Nutr Metab. 2021 May;46(5):452-460. doi: 10.1139/apnm-2020-0404. Epub 2020 Oct 30.
Maintaining a critical amount of skeletal muscle mass is linked to reduced morbidity and mortality. In males, testicular androgens regulate muscle mass with a loss of androgens being critical as it is associated with muscle atrophy. Atrophy of the limb muscles is particularly important, but the pathways by which androgens regulate limb muscle mass remain equivocal. We used microarray analysis to identify changes to genes involved with polyamine metabolism in the tibialis anterior (TA) muscle of castrated mice. Of the polyamines, the concentration of spermidine (SPD) was significantly reduced in the TA of castrated mice. To assess whether SPD was an independent factor by which androgens regulate limb muscle mass, we treated castrated mice with SPD for 8 weeks and compared them with sham operated mice. Though this treatment paradigm effectively restored SPD concentrations in the TA muscles of castrated mice, mass of the limb muscles (i.e., TA, gastrocnemius, plantaris, and soleus) were not increased to the levels observed in sham animals. Consistent with those findings, muscle force production was also not increased by SPD treatment. Overall, these data demonstrate for the first time that SPD is not an independent factor by which androgens regulate limb skeletal muscle mass. Polyamines regulate growth in various cells/tissues. Spermidine concentrations are reduced in the limb skeletal muscle following androgen depletion. Restoring spermidine concentrations in the limb skeletal muscle does not increase limb muscle mass or force production.
维持足够的骨骼肌量与降低发病率和死亡率有关。在男性中，睾丸雄激素调节肌肉量，雄激素的丧失至关重要，因为它与肌肉萎缩有关。肢体肌肉的萎缩尤其重要，但雄激素调节肢体肌肉量的途径仍存在争议。我们使用微阵列分析来鉴定去势小鼠比目鱼肌中参与多胺代谢的基因变化。在多胺中，精脒（SPD）的浓度在去势小鼠的比目鱼肌中显著降低。为了评估 SPD 是否是雄激素调节肢体肌肉量的独立因素，我们用 SPD 治疗去势小鼠 8 周，并将其与假手术小鼠进行比较。尽管这种治疗方案有效地恢复了去势小鼠比目鱼肌中 SPD 的浓度，但肢体肌肉（即比目鱼肌、腓肠肌、跖肌和比目鱼肌）的质量并没有增加到假动物观察到的水平。与这些发现一致，SPD 治疗也没有增加肌肉力量的产生。总的来说，这些数据首次表明 SPD 不是雄激素调节肢体骨骼肌肉量的独立因素。多胺调节各种细胞/组织的生长。雄激素耗竭后，肢体骨骼肌中的精脒浓度降低。在肢体骨骼肌中恢复精脒浓度并不能增加肢体肌肉的质量或力量的产生。
