Loss of skeletal muscle mass and strength is often associated with disability and poor quality of life. Selective Androgen Receptor Modulators (SARMs) are under development as potential treatment. This study aims at examining the potential of wild bitter gourd (BG) as a SARM and its effects on the muscle decline induced by orchiectomy. In the cell-based androgen receptor (AR) transactivation assay, the BGP extract showed weak agonistic and antagonistic activities, resembling those of some SARMs. Male C57BL/6J mice were sham-operated (Sham group) or castrated (Cast groups) and fed a modified AIN-93G high sucrose diet supplemented without (Cast group) or with 5% lyophilized BG powder (Cast + BGP) or with testosterone propionate (7 mg TP per kg diet, Cast + TP) for 23 weeks. In contrast to the Cast + TP group, the BGP supplementation did not affect the serum testosterone concentration, and prostate and seminal vesicle mass. Both TP and BGP supplementation increased the weight of androgen responsive muscles, bulbocavernosus (BC) and levator ani (LA) (p < 0.05). The grip strength and the performance on a rotarod of the Cast + BGP group were comparable to those of the Cast + TP group (p > 0.05). The number of succinate dehydrogenase (SDH)-positive fibers of the Cast + BGP group was not significantly different from that of the Sham and Cast + TP groups (p > 0.05). The BGP supplementation up-regulated the Pgc1α, Ucp2 or Ucp3 gene expressions in skeletal muscles of castrated mice (p < 0.05). BGP showed some characteristics of the SARM and might improve skeletal muscle function through the up-regulation of mitochondrial biogenic genes and oxidative capacity, and ameliorated the castration-induced decline of skeletal muscle function in mice.

中文翻译：

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日粮野生苦瓜显示出选择性的雄激素受体调节剂活性，并改善了经睾丸切除的小鼠的肌肉衰退能力†

骨骼肌质量和力量的丧失通常与残疾和生活质量低下有关。选择性雄激素受体调节剂（SARM）正在开发中作为潜在的治疗方法。这项研究旨在检查野生苦瓜（BG）作为SARM的潜力及其对睾丸切除术引起的肌肉萎缩的影响。在基于细胞的雄激素受体（AR）反式激活分析中，BGP提取物表现出弱的激动和拮抗活性，类似于某些SARM的激动和拮抗活性。假手术（假手术组）或cast割（铸造组）的雄性C57BL / 6J小鼠，饲喂改良的AIN-93G高蔗糖饮食，补充不使用（铸造组）或5％冻干的BG粉（铸造+ BGP）或睾丸激素丙酸酯（每公斤日粮7毫克TP，精制+ TP）持续23周。与Cast + TP组相比，BGP补充剂不会影响血清睾丸激素的浓度以及前列腺和精囊的质量。TP和BGP的补充均增加了雄激素反应性肌肉，球海绵肌（BC）和肛提肌（LA）的重量（p＜0.05）。Cast + BGP组的握柄强度和在旋转脚架上的性能与Cast + TP组的握柄强度和性能相当（p > 0.05）。Cast + BGP组的琥珀酸脱氢酶（SDH）阳性纤维数目与Sham和Cast + TP组的数目无显着差异（p > 0.05）。BGP补充上调了去势小鼠骨骼肌中Pgc1α，Ucp2或Ucp3基因的表达（p<0.05）。BGP显示出SARM的某些特征，并可能通过上调线粒体生物基因和氧化能力来改善骨骼肌功能，并改善了去势诱发小鼠骨骼肌功能的下降。