Cavalié H, Lac G, Lebecque P, Chanteranne B, Davicco M-J, Barlet J-P
Laboratoire de la Performance Motrice, Université Blaise Pascal, Clermont-Ferrand, 63177 Aubière, France.
J Appl Physiol (1985). 2002 Dec;93(6):2034-7. doi: 10.1152/japplphysiol.00472.2002.
This paper reports that the selective beta(2)-adrenergic receptor agonist clenbuterol affects bone metabolism in growing 3-mo-old male Wistar rats treated over 8 wk. Thirty-two 3-mo-old growing Wistar rats weighing 234 +/- 2 g were assigned to a progressive isometric force, strength-training exercise program plus oral clenbuterol (2 mg x kg body wt(-1) x day(-1)) for 5 days each week, exercise program without clenbuterol 5 days each week, no exercise program plus oral clenbuterol (2 mg x kg(-1) x day(-1)) for 5 days each week, or no exercise without clenbuterol 5 days each week. At the end of 8 wk, lean mass, fat mass, and right total femoral, distal metaphyseal femoral, and diaphyseal femoral bone mineral density were measured by Hologic QDR 4,500 dual X-ray absorptiometry (DEXA) technique. Left femoral bones were harvested after death on day 58, and femoral resistance was determined by three-point bending testing. We found that fat mass was decreased in rats given strength training exercise and decreased further in rats treated with clenbuterol. Lean mass was increased in clenbuterol-treated animals. Strength-training exercise appeared to have no effect on bone mineral density, serum osteocalcin, or urinary deoxypyridinoline. However, clenbuterol treatment decreased femoral length, diameter, bone mineral density, and mechanical resistance. Clenbuterol had no effect on osteocalcin but increased urinary deoxypyridinoline. We concluded that clenbuterol treatment decreased bone mineral density and increased bone resorption independent of the level of exercise rats were given.
本文报道，选择性β₂-肾上腺素能受体激动剂克仑特罗对8周龄的3月龄雄性Wistar生长大鼠的骨代谢有影响。将32只体重为234±2 g的3月龄生长Wistar大鼠分为四组：一组进行渐进性等长力量训练运动计划并每周5天口服克仑特罗（2 mg·kg体重⁻¹·天⁻¹）；一组进行运动计划但不使用克仑特罗，每周5天；一组不进行运动计划但每周5天口服克仑特罗（2 mg·kg⁻¹·天⁻¹）；一组既不进行运动也不使用克仑特罗，每周5天。8周结束时，采用Hologic QDR 4500双能X线吸收测定法（DEXA）测量瘦体重、脂肪量以及右侧股骨全长、股骨远端干骺端和骨干的骨矿物质密度。在第58天处死动物后采集左侧股骨，通过三点弯曲试验测定股骨阻力。我们发现，进行力量训练运动的大鼠脂肪量减少，而使用克仑特罗治疗的大鼠脂肪量进一步减少。使用克仑特罗治疗的动物瘦体重增加。力量训练运动似乎对骨矿物质密度、血清骨钙素或尿脱氧吡啶啉没有影响。然而，克仑特罗治疗使股骨长度、直径、骨矿物质密度和力学阻力降低。克仑特罗对骨钙素没有影响，但增加了尿脱氧吡啶啉。我们得出结论，克仑特罗治疗降低了骨矿物质密度并增加了骨吸收，且与大鼠的运动水平无关。
