Katz Y, Amiri Z, Weizman A, Gavish M
Department of Pharmacology, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Biochem Pharmacol. 1990 Aug 15;40(4):817-20. doi: 10.1016/0006-2952(90)90321-b.
In the present study we identified and characterized the distribution of high-affinity peripheral benzodiazepine binding sites (PBzS) in male rat vas deferens (whole, and prostatic and epididymal portions), prostate, seminal vesicles, and Cowper's glands. [3H]PK 11195, an isoquinoline carboxamide derivative, was used as a radioligand specific for PBzS. Scatchard analysis of saturation curves of [3H]PK 11195 binding in the whole vas deferens, the prostatic and epididymal portions of the vas deferens, the prostate, the seminal vesicles, and Cowper's glands yielded mean maximal numbers of binding sites of 1211 +/- 158, 1012 +/- 311, 1451 +/- 156, 1805 +/- 86, 865 +/- 51, and 2251 +/- 135 fmol/mg protein, respectively. The equilibrium dissociation constant values ranged between 1 and 3 mM in all the above tissues. The ability of various drugs to displace the specific binding of [3H]PK 11195 from PBzS in Cowper's gland membranes was also tested. The inhibition constants for Ro 5-4864, diazepam, and PK 11195 were 28, 330, and 4 nM, respectively, whereas clonazepam, Ro 15-1788, and testosterone were inefficient in displacing [3H]PK 11195. The presence of high densities of PBzS in the male genital tract suggests a functional role in these hormone-dependent organs.
在本研究中，我们鉴定并描述了雄性大鼠输精管（整体、前列腺部和附睾部）、前列腺、精囊和尿道球腺中高亲和力外周苯二氮䓬结合位点（PBzS）的分布情况。异喹啉甲酰胺衍生物[³H]PK 11195用作PBzS的特异性放射性配体。对[³H]PK 11195在输精管整体、输精管前列腺部和附睾部、前列腺、精囊以及尿道球腺中的结合饱和曲线进行Scatchard分析，得到的结合位点平均最大数量分别为1211±158、1012±311、1451±156、1805±86、865±51和2251±135 fmol/mg蛋白质。上述所有组织中的平衡解离常数在1至3 mM之间。我们还测试了多种药物从尿道球腺膜中的PBzS取代[³H]PK 11195特异性结合的能力。Ro 5 - 4864、地西泮和PK 11195的抑制常数分别为28、330和4 nM，而氯硝西泮、Ro 15 - 1788和睾酮在取代[³H]PK 11195方面效率不高。雄性生殖道中高密度PBzS的存在表明其在这些激素依赖性器官中具有功能作用。
