Zhang R, An C, Chen M
Department of Biochemistry, Pharmaceutical College.
Hua Xi Yi Ke Da Xue Xue Bao. 1995 Sep;26(3):257-60.
It has been documented that there are specific human chorionic gonadotropin (HCG) receptors in cell membrane of rat ovary and testicle. In order to make a further study on the characteristics of the HCG receptors on rat ovary and testicle, we focused on comparing those two kinds of receptors. Furthermore, we contrasted the testicular cell membrane with its homogenates. Rat ovarian and testicles were homogenized and soniced under ice cold conditions. The homogenates were centrifuged at 12,100 x g for 20 min following filtration. After sucrose density gradient ultracentrifugation (78,000 x g, 2.5h) for the pellets, the interface layers between 37% and 41% were collected. The pellets were subsequently suspended in cold 1mmol/L NaHCO3 solution and recentrifuged at 27,000 x g for 25 min. The results show that the cell membrane of both the rat ovary and testicle can bind to HCG specifically. A small amount of HCG has more evident inhibitory effect on the binding in testis than ovary. Scatchard plot analysis for the binding assay yielded a bound capacity of testicle cell membrane of 4.5 x 10(-5) mol/micrograms protein, Kd of 1.6 x 10(-7) mol/L, whereas it was 0.51 x 10(-9) mol/micrograms protein, a Kd of 1.69 x 10(-6) mol/L in ovarian cell membrane. In comparison with homogenates and cell membrane, the HCG binding activity of later is more sensitive.
据记载，大鼠卵巢和睾丸细胞膜上存在特异性人绒毛膜促性腺激素（HCG）受体。为了进一步研究大鼠卵巢和睾丸上HCG受体的特性，我们着重比较了这两种受体。此外，我们还将睾丸细胞膜与其匀浆进行了对比。在冰冷条件下将大鼠卵巢和睾丸匀浆并超声处理。匀浆经过滤后以12,100×g离心20分钟。对沉淀进行蔗糖密度梯度超速离心（78,000×g，2.5小时）后，收集37%和41%之间的界面层。随后将沉淀悬浮于冷的1mmol/L NaHCO₃溶液中，并以27,000×g再次离心25分钟。结果表明，大鼠卵巢和睾丸的细胞膜均能特异性结合HCG。少量HCG对睾丸中结合的抑制作用比对卵巢更明显。结合试验的Scatchard图分析得出，睾丸细胞膜的结合容量为4.5×10⁻⁵mol/μg蛋白质，Kd为1.6×10⁻⁷mol/L，而卵巢细胞膜的结合容量为0.51×10⁻⁹mol/μg蛋白质，Kd为1.69×10⁻⁶mol/L。与匀浆和细胞膜相比，后者的HCG结合活性更敏感。
