正常生育男性精子膜孕激素受体的放射性配基结合分析

目的:研究体外获能2h后正常生育男性精子膜上的孕酮结合位点。方法:用上游法分离活力良好的精子并于体外获能2h,然后进行多点结合饱和实验,在7个总结合管内分别加入精子悬液和浓度递增的孕酮-11α-葡萄糖醛酸甙-125I]碘化酪胺(125I-孕酮),在相应的非特异管内除加入与总结合管等量的精子悬液和125I-孕酮外,另加入10μmol/L孕酮,于4℃孵育1h,终止孵育后分别测定各管以及离心后沉淀的放射性,运用Scatchard函数的单位点多点饱和法数学模型,用最小二乘回归法计算平衡解离常数(Kd)和最大结合容量(Bmax)。结果:Kd为(0.61±0.04)nmol/L,Bmax为(830±344)结合位点数/细胞,对回归方程进行的显著性检验表明r=-0.980,P<0.01。结论:正常生育男性精子膜上存在一种高亲和力和低容量性孕酮结合位点即孕激素受体。

Radioligand Binding Assay of Progesterone Receptors on Normal Fertile Human Sperm Membrane

OBJECTIVE: To investigate the progesterone-binding site on the normal fertile human sperm membrane after 2 hours of in vitro capacitation. METHODS: Viable spermatozoa were selected by a swim-up method. After 2 hours of in vitro capacitation, multipoint saturation binding experiments were performed. Sperm suspension and increasing concentrations of progesterone-11alpha-glucuronide-125I] iodotyramine (125I-P) were added to 7 total binding tubes respectively, and equal amounts of sperm suspension and 125I-P were added to another 7 corresponding non-specific binding tubes in the presence of 10 micromol/L progesterone. After incubation for 1 hour at 4 degrees C, the radioactivity of both the tubes and the pellets after centrifugation was measured respectively. The equilibrium dissociation constant (Kd) and maximum binding capacity (Bmax) were calculated using the mathematical model of single site multi-point saturation method of Scatchard function and least-squares regression. RESULTS: Kd was (0.61 +/- 0.04) nmol/L and Bmax was (830 +/- 344) sites/cell. The significance test of the regression equation indicated that r = -0.980, P < 0.01. CONCLUSION: There is a high affinity and low capacity binding site for the progesterone (progesterone receptor) on the normal fertile human sperm membrane.