Different effects of enantiomers of beta2-adrenergic agonist on muscle and bone.

当（-）-（R）-和（+）-（S）-2-肾上腺素受体（β 2-AR）拮抗剂Tulobuterol （每个10毫克/千克）在4周内被轻微地注射到女性年轻老鼠身上，每次测试肌肉和骨骼上的每一种毒性都会产生影响。（-）-（R）-能量体，但不是（+）-（S）-能量体，明显增加了身体的重量和减少的脂肪，与车辆控制比较。具体地说，（R）-映体不仅增加了心脏麝香和骨骼麝香，但转移了麝香乳酸脱氢酶（LDH）的同位素从H型到M型，也是肌红蛋白重链（HMC）的同位素模式从慢型到快型。在另一只手上，（S）-映体减少了骨骼矿物密度，并伴随着尿氧嘧啶提取物的增加。体外、奥氏体样细胞形成是在共同培养中产生的，小鼠骨骼marrow细胞（BMC）和ST 2-T细胞为7天准备的，用（S）-比（R）-enantiomer处理。因此，它被选择性β 2-AR抑制剂butoxamine和非选择性β-AR抑制剂propranolol抑制剂抑制。（R）-β 2-AR治疗师对运动员和运动员的影响应该是方便的，但（S）-AR治疗师可能会影响年轻用户的骨骼生长和增加骨骼碎片的风险，特别是当使用非法剂量作为药物时。本研究是第一份报告，描述了β 2-AR抑制剂对肌肉和骨骼的不同活动的（R）-和（S）-的影响。我们需要携带“racemiswitch”来开发一种药物，以确保有效的活性异构体。

When (-)-(R)- and (+)-(S)-enantiomers of ・2-adrenergic receptor (β2-AR) agonist tulobuterol (each 10 mg/kg) was subcutaneously injected into female young rats once a day for 4 weeks, the effects of each enantiomer on the muscle and bone were examined. The (-)-(R)-enantiomer, but not (+)-(S)-enantiomer, significantly increased the body weight and decreased fat, compared with vehicle control. Particularly, the (R)-enantiomer not only increased the heart muscle and skeletal muscle but shifted the muscle lactate dehydrogenase (LDH) isoenzyme from the H-type to M-type and also myosin heavy chain (HMC) isoform pattern from slow type to fast type. On the other hand, the (S)-enantiomer decreased the bone mineral density, accompanied with increase in urinary deoxypyridinoline excretion. In vitro, osteoclast-like cell formation were generated in co-culture, mouse bone marrow cells (BMC) and ST2-T cells preparations for 7 days, treated with (S)-enantiomer more than with (R)-enantiomer. Moreover, it was inhibited by selective β2-AR inhibitor butoxamine and non-selective β-AR inhibitor propranolol. The effects of (R)-enantiomer of β2-AR agonist should be convenient for athletes and exercisers, but the (S)-enantiomer might influence the bone growth and increase the risk of bone fracture in young users, in particular when used illegal dosage as doping. This study is the first report indicating the different activities of (R)- and (S)-enantiomers of β2-AR agonist on the muscle and bone. We need to carry out “racemiswitch” to develop drugs consisting useful active enantiomer.