Choo J J, Horan M A, Little R A, Rothwell N J
Department of Physiological Sciences, University of Manchester, UK.
Biosci Rep. 1989 Oct;9(5):615-21. doi: 10.1007/BF01119805.
A single injection of endotoxin (1 mg/kg, sc) in rats caused significant fever, body weight loss and reduction in gastrocnemius muscle mass, none of which was mimicked by pair-feeding. Infusion of endotoxin via osmotic minipump over five days caused transient fever and suppression of growth. Recovery of body weight was significantly enhanced by the administration of the beta 2-adrenoceptor agonist clenbuterol (added to the diet at 4 mg/kg). In a separate experiment, injections of endotoxin (day 0 and day 2) caused significant reductions in body weight gain (42%), mass (9%) and protein content (13%) of gastrocnemius muscle over 3 days. Addition of clenbuterol to the diet reversed all of these effects but did not alter food intake or the febrile response to endotoxin. Clenbuterol caused large (20%) increases in the ratio of RNA to protein in muscle indicating that it may have stimulated protein synthesis. beta 2-adrenoceptor agonists may therefore be of value in preventing or inhibiting muscle atrophy associated with infection or injury.
给大鼠单次皮下注射内毒素（1毫克/千克）可导致明显发热、体重减轻以及腓肠肌质量减少，而配对喂养并未出现这些情况。通过渗透微型泵连续五天输注内毒素会引起短暂发热并抑制生长。给予β2肾上腺素能受体激动剂克仑特罗（以4毫克/千克的剂量添加到饮食中）可显著促进体重恢复。在另一项实验中，注射内毒素（第0天和第2天）导致3天内腓肠肌的体重增加（42%）、质量（9%）和蛋白质含量（13%）显著降低。在饮食中添加克仑特罗可逆转所有这些影响，但不改变食物摄入量或对内毒素的发热反应。克仑特罗使肌肉中RNA与蛋白质的比例大幅增加（20%），表明它可能刺激了蛋白质合成。因此，β2肾上腺素能受体激动剂在预防或抑制与感染或损伤相关的肌肉萎缩方面可能具有价值。
