Hayashida D N, Leung R, Goldfien A, Roberts J M
Am J Obstet Gynecol. 1982 Feb 15;142(4):389-93. doi: 10.1016/s0002-9378(16)32378-x.
The radioactive beta-adrenergic antagonist [3H] dihydroalprenolol (DHA) binds to particulate preparations of human myometrium in a manner compatible with binding to the beta-adrenergic receptor. The binding of DHA is rapid (attaining equilibrium in 12 minutes), readily reversible (half time = 16 minutes), high affinity (KD = 0.50 nM), low capacity (Bmax = 70 fmoles/mg of protein), and stereoselective ([-]-propranolol is 100 times as potent as [+]-ipropranolol in inhibiting DHA binding). Adrenergic agonists competed for DHA binding sites in a manner compatible with beta-adrenergic interactions and mirrored beta 2 pharmacologic potencies: isoproterenol greater than epinephrine much greater than norepinephrine. Studies in which zinterol, a beta 2-adrenergic agonist, competed for DHA binding sites in human myometrial particulate indicated that at least 87% of the beta-adrenergic receptors present are beta 2-adrenergic receptors. Binding of DHA to human myometrial beta-adrenergic receptors provides a tool which may be used in the examination of gonadal hormonal modification of adrenergic response in human uterus as well as in the analysis of beta-adrenergic agents as potentially useful tocolytic agents.
放射性β-肾上腺素能拮抗剂[3H]二氢心得舒（DHA）以与β-肾上腺素能受体结合相一致的方式与人子宫肌层微粒体制剂结合。DHA的结合迅速（12分钟达到平衡）、易于逆转（半衰期=16分钟）、亲和力高（KD = 0.50 nM）、容量低（Bmax = 70 fmol/mg蛋白质）且具有立体选择性（[-]-普萘洛尔在抑制DHA结合方面的效力是[+]-异丙普萘洛尔的100倍）。肾上腺素能激动剂以与β-肾上腺素能相互作用相一致的方式竞争DHA结合位点，并反映了β2药理学效力：异丙肾上腺素＞肾上腺素＞去甲肾上腺素。β2肾上腺素能激动剂辛特罗竞争人子宫肌层微粒体中DHA结合位点的研究表明，存在的β-肾上腺素能受体中至少87%是β2肾上腺素能受体。DHA与人子宫肌层β-肾上腺素能受体的结合提供了一种工具，可用于研究性腺激素对人子宫肾上腺素能反应的修饰，以及分析β-肾上腺素能药物作为潜在有用的宫缩抑制剂。
