Almond R E, Enser M
AFRC Institute of Food Research, Langford, Bristol, UK.
Int J Obes. 1989;13(6):791-800.
Adrenalectomy of obese mice increases the weights of their skeletal muscles towards normal. We have investigated whether this increased growth was specific for the fast phasic muscles and white, glycolytic fibres most affected by obesity and whether the proportions of the different fibre types were restored to normal. Male obese hyperglycaemic mice (ob/ob) and lean mice were adrenalectomized at 6 weeks of age and examined 6 weeks later. In obese mice body weight gain and blood glucose were markedly decreased, although still higher than in lean mice. The weight of the heart was decreased to normal in obese mice and unaffected in lean mice. In lean mice the weights of the biceps brachii, gastrocnemius and soleus muscles increased by similar small amounts after adrenalectomy. In obese mice the fast gastrocnemius and biceps brachii recovered most in weight, the soleus somewhat less, but all remained smaller than in lean adrenalectomized mice. The increased growth of the biceps brachii in obese mice after adrenalectomy was non-specific with a similar increase in size of all fibre types, including the fast red fibres which were not affected by obesity. Fibre type proportions were not normalized by adrenalectomy of obese mice but were significantly changed in adrenalectomized lean mice. We conclude that it is possible only partially to normalize muscle weight and fibre type composition in obese mice by adrenalectomy. We suppose that its effects are manifest because of other defects such as insulin resistance and that these are not all reversed by adrenalectomy.
对肥胖小鼠进行肾上腺切除可使它们的骨骼肌重量向正常水平增加。我们研究了这种增加的生长是否特定于快速收缩肌以及肥胖影响最严重的白色糖酵解纤维，还研究了不同纤维类型的比例是否恢复正常。雄性肥胖高血糖小鼠（ob/ob）和瘦小鼠在6周龄时进行肾上腺切除，并在6周后进行检查。肥胖小鼠的体重增加和血糖明显降低，尽管仍高于瘦小鼠。肥胖小鼠的心脏重量降至正常，而瘦小鼠的心脏重量未受影响。在瘦小鼠中，肾上腺切除后肱二头肌、腓肠肌和比目鱼肌的重量有相似的少量增加。在肥胖小鼠中，快速收缩的腓肠肌和肱二头肌重量恢复最多，比目鱼肌恢复较少，但都仍小于瘦的肾上腺切除小鼠。肥胖小鼠肾上腺切除后肱二头肌的生长增加是非特异性的，所有纤维类型包括不受肥胖影响的快速红纤维大小都有相似增加。肥胖小鼠肾上腺切除并未使纤维类型比例恢复正常，但在肾上腺切除的瘦小鼠中纤维类型比例有显著变化。我们得出结论，通过肾上腺切除只能使肥胖小鼠的肌肉重量和纤维类型组成部分恢复正常。我们推测其作用之所以显现是因为存在其他缺陷，如胰岛素抵抗，而这些缺陷并非都能通过肾上腺切除得到逆转。
