Carter W J, Dang A Q, Faas F H, Lynch M E
Veterans Administration Medical Center, Little Rock, AR.
Metabolism. 1991 Aug;40(8):855-60. doi: 10.1016/0026-0495(91)90015-o.
Aging decreases skeletal muscle mass and strength, which may be exacerbated by age-related diseases. There is a need for therapeutic agents to prevent or restore loss of skeletal muscle in elderly subjects with muscle wasting disorders. Clenbuterol, a beta 2-adrenergic agonist, dramatically increases skeletal muscle mass in young animals and partially prevents or restores muscle loss in experimental models of muscle wasting. However, the protein anabolic and fat catabolic effects of clenbuterol have not been studied in senescent animals. To determine whether this drug has potential for preventing or repairing muscle loss in elderly subjects, we have examined its effects in young and old rats. Clenbuterol was administered by implanted osmotic minipumps to Fischer-344 rats ages 3, 12, and 23 months, at a dose of 1.5 mg/kg/24 h for 3 weeks. The weights of five hindlimb muscles and carcass protein and fat content were determined. Clenbuterol treatment increased the weight of skeletal muscles 22% to 39% in 3-month-old rats, 19% to 35% in 12-month-old rats, and 22% to 25% in 23-month-old animals. Likewise, clenbuterol increased carcass protein content 19% in 3-month-old rats, 16% in 12-month-old rats, and 24% in 23-month-old animals. Conversely, the drug reduced carcass fat content 36% in 3-month-old rats, 32% in 12-month-old rats, and 38% in 23-month-old rats. Therefore, clenbuterol had similar anabolic and catabolic effects in all age groups. In addition, clenbuterol stimulated recovery of skeletal muscle protein lost following pump implantation in senescent rats.(ABSTRACT TRUNCATED AT 250 WORDS)
衰老会导致骨骼肌质量和力量下降，而与年龄相关的疾病可能会加剧这种情况。对于患有肌肉萎缩症的老年受试者，需要有治疗药物来预防或恢复骨骼肌的流失。克仑特罗是一种β2肾上腺素能激动剂，能显著增加幼龄动物的骨骼肌质量，并在肌肉萎缩的实验模型中部分预防或恢复肌肉流失。然而，尚未在衰老动物中研究克仑特罗的蛋白质合成代谢和脂肪分解代谢作用。为了确定这种药物是否有预防或修复老年受试者肌肉流失的潜力，我们研究了它对年轻和老年大鼠的影响。通过植入式渗透微型泵给3个月、12个月和23个月大的Fischer-344大鼠施用克仑特罗，剂量为1.5毫克/千克/24小时，持续3周。测定了五条后肢肌肉的重量以及胴体蛋白质和脂肪含量。克仑特罗治疗使3个月大的大鼠骨骼肌重量增加了22%至39%，12个月大的大鼠增加了19%至35%，23个月大的动物增加了22%至25%。同样，克仑特罗使3个月大的大鼠胴体蛋白质含量增加了19%，12个月大的大鼠增加了16%，23个月大的动物增加了24%。相反，该药物使3个月大的大鼠胴体脂肪含量降低了36%，12个月大的大鼠降低了32%，23个月大的大鼠降低了38%。因此，克仑特罗在所有年龄组中都有类似的合成代谢和分解代谢作用。此外，克仑特罗促进了衰老大鼠泵植入后骨骼肌蛋白质损失的恢复。（摘要截短于250字）
