Svoboda P, Svartengren J, Snochowski M, Houstĕk J, Cannon B
Eur J Biochem. 1979 Dec;102(1):203-10. doi: 10.1111/j.1432-1033.1979.tb06281.x.
The beta-adrenergic receptors of hamster brown adipocytes have been characterised by binding of the radioactive ligand (-)-[3H]dihydroalprenolol, directly to isolated intact cells in suspension. The brown fat cell contains 57,000 specific and saturable binding sites which have a dissociation constant (Kd) for [3H]dihydroalprenolol of 1.4 nM as determined by Scatchard analysis. The kinetically derived Kd, determined from forward and reverse rate constants, is 5 nM. Both of these values are in agreement with the dissociation constant (Kd = 2.2 nM) for alprenolol, determined from competition studies with [3H]dihydroalprenolol in these cells. Beta-adrenergic agonists competed for the specific binding sites with a typical beta 1-adrenergic specificity. The order of potency of agonists agrees well with the ability of these agents to stimulate respiration in isolated brown adipocytes: 50% stimulation of respiration occurs with apparently less than 10% occupancy of binding sites. Both the high affinity and high number of specific binding sites of [3H]dihydroalprenolol in brown fat cells presumably reflect the generally accepted dominating role of catecholamines in the regulation of brown fat metabolism and non-shivering thermogenesis.
仓鼠棕色脂肪细胞的β-肾上腺素能受体已通过放射性配体（-）-[³H]二氢阿普洛尔与悬浮状态下分离的完整细胞直接结合进行了表征。棕色脂肪细胞含有57,000个特异性且可饱和的结合位点，通过Scatchard分析确定，这些位点对[³H]二氢阿普洛尔的解离常数（Kd）为1.4 nM。根据正向和反向速率常数动力学推导得出的Kd为5 nM。这两个值均与通过在这些细胞中用[³H]二氢阿普洛尔进行竞争研究确定的阿普洛尔的解离常数（Kd = 2.2 nM）一致。β-肾上腺素能激动剂以典型的β1-肾上腺素能特异性竞争特异性结合位点。激动剂的效力顺序与这些药物刺激分离的棕色脂肪细胞呼吸的能力非常吻合：呼吸刺激50%时，结合位点的占有率明显低于10%。棕色脂肪细胞中[³H]二氢阿普洛尔的高亲和力和大量特异性结合位点可能反映了儿茶酚胺在棕色脂肪代谢和非颤抖性产热调节中普遍公认的主导作用。
