Lafontan M, Berlan M, Prud'Hon M
Institut de Physiologie, UA 644 C.N.R.S., Université Paul Sabatier, Toulouse, France.
Reprod Nutr Dev (1980). 1988;28(1):61-84.
In this review, the results obtained in commercial livestock with certain beta-adrenergic agonists (clenbuterol and cimaterol) having an anabolic potential associated with lipid mobilizing properties are considered. The first chapter summarizes major data concerning the effects of beta-agonists on growth and carcass composition in cattle, sheep and pigs. The effect of clenbuterol and cimaterol on carcass quality is to increase the deposition of protein while reducing fat accretion. Then, we briefly consider the physiology and pharmacology of the sympathoadrenal system with a special attention to the distribution and properties of beta-adrenoceptors of various tissues which are putative targets for the beta-adrenergic agonists. Several mechanisms liable to be responsible for the anabolic action of these compounds are also discussed. This chapter includes the evaluation of the effects of beta-agonist on central nervous system and pancreas. A special attention is devoted to their metabolic impact on adipose tissue and muscle. In isolated fat cells, beta-agonists promote stimulation of lipolysis associated with reduction of lipogenesis and of insulin action. The in vitro effects on adipocytes are consistent with the in vivo effects of the compounds. Beta-agonist impact on protein synthesis and muscle accretion is also discussed with reference: 1) to the vascular effects of the compounds that should modify the nutrient flow into the muscle, 2) to a reduction of proteolysis mainly observed for the moment in in vitro studies, 3) to the possible beta-adrenergic-dependent enhancement of insulin action on the muscle. However, more direct experimental evidence is still needed to clearly assess the nature of the action(s) of such anabolic agents on muscle.
在本综述中，我们考虑了在商业养殖家畜中使用某些具有合成代谢潜力且与脂质动员特性相关的β-肾上腺素能激动剂（克伦特罗和西马特罗）所获得的结果。第一章总结了有关β-激动剂对牛、羊和猪生长及胴体组成影响的主要数据。克伦特罗和西马特罗对胴体品质的影响是增加蛋白质沉积，同时减少脂肪蓄积。然后，我们简要探讨了交感肾上腺系统的生理学和药理学，特别关注各种组织中β-肾上腺素能受体的分布和特性，这些组织是β-肾上腺素能激动剂的假定作用靶点。还讨论了可能导致这些化合物合成代谢作用的几种机制。本章包括对β-激动剂对中枢神经系统和胰腺影响的评估。特别关注它们对脂肪组织和肌肉的代谢影响。在分离的脂肪细胞中，β-激动剂促进脂解刺激，同时伴有脂肪生成减少和胰岛素作用减弱。对脂肪细胞的体外作用与这些化合物的体内作用一致。还参考以下方面讨论了β-激动剂对蛋白质合成和肌肉生长的影响：1）化合物的血管效应，这应会改变营养物质向肌肉的流动；2）主要在体外研究中目前观察到的蛋白水解减少；3）β-肾上腺素能依赖性增强胰岛素对肌肉作用的可能性。然而，仍需要更直接的实验证据来明确评估此类合成代谢剂对肌肉作用的性质。
