Raikar R S, Dattatreyamurty B, Sheth A R
Endocrinol Exp. 1981;15(1):55-64.
The presence of a specific prolactin binding in rat seminal vesicle fluid has been demonstrated. The binding phenomenon was saturable and pH dependent, the optimum pH being 7.2. The prolactin binding protein (PBP, 1800 x g supernatant) was characterized by a single order affinity binding sites with an association constant (Ka) 1.52 x 10(7) mol-1. The specificity of the prolactin binding was demonstrated by the fact that other proteohormones such as rFSH, rLH, rTSH and hTSH failed to inhibit the binding of labelled hormone to PBP, while unlabelled oPRL gave a dose-response inhibition curve. Among the rats in the age group 45 to 180 days, PBP obtained from animals of 90 day old showed a maximum binding of radioiodinated rPRL. Following castration for five days the percent binding of 125I-rPRL to PBP decreased markedly. The treatment of castrated rats with testosterone propionate for five days returned the 125I-rPRL binding to near intact values. Following a centrifugation of 1800 x g supernatant at 360 000 x g for 3 h, prolactin binding activity still remained in the supernatant thus implicating that the binding protein is in a soluble state.
已证实在大鼠精囊液中存在特异性催乳素结合。这种结合现象具有饱和性且依赖于pH值，最适pH为7.2。催乳素结合蛋白（PBP，1800×g上清液）具有单级亲和结合位点，其缔合常数（Ka）为1.52×10⁷ mol⁻¹。催乳素结合的特异性体现在以下事实：其他蛋白激素，如rFSH、rLH、rTSH和hTSH，不能抑制标记激素与PBP的结合，而未标记的oPRL则给出剂量反应抑制曲线。在45至180天龄的大鼠中，从90日龄动物获得的PBP对放射性碘化rPRL的结合量最大。阉割5天后，¹²⁵I-rPRL与PBP的结合百分比显著下降。用丙酸睾酮对阉割大鼠进行5天治疗后，¹²⁵I-rPRL的结合恢复到接近完整的值。将1800×g上清液在360 000×g下离心3小时后，催乳素结合活性仍保留在上清液中，这表明结合蛋白处于可溶状态。
