Costlow M E, Sluyser M, Gallagher P E
Endocr Res Commun. 1977;4(5):285-94. doi: 10.3109/07435807709052948.
Prolactin receptors have been identified in estrone-progesterone induced mammary tumors from GR mice. 125I-labeled ovine prolactin binding to tumor homogenates reached a steady state in 12 hours at 22 degrees and was specific for prolactin. Prolactin receptors were highest (16 fmoles/mg protein) in primary, hormone-dependent tumors and declined progressively in transplanted hormone-dependent and transplanted hormone-responsive tumors. In autonomous tumors, binding was approximately 5% of that found in primary tumors. Scatchard analysis of binding to selected tumors indicated that the observed decrease in bound hormone was due to a loss in the number of receptor sites; binding affinity was unaltered (kd approximately 1 X 10(-10) M). Since receptors for estrogen and progesterone as well as those for prolactin decline in a concerted manner with the transition to autonomy, autonomous growth may result from a loss of receptors or an increase in the relative proportion of autonomous cells present in the tumor.
在雌激素 - 孕酮诱导的GR小鼠乳腺肿瘤中已鉴定出催乳素受体。在22摄氏度下，125I标记的绵羊催乳素与肿瘤匀浆的结合在12小时内达到稳态，且对催乳素具有特异性。催乳素受体在原发性激素依赖性肿瘤中含量最高（16飞摩尔/毫克蛋白质），而在移植的激素依赖性肿瘤和移植的激素反应性肿瘤中逐渐减少。在自主性肿瘤中，结合量约为原发性肿瘤中的5%。对选定肿瘤结合情况的Scatchard分析表明，观察到的结合激素减少是由于受体位点数量的减少；结合亲和力未改变（解离常数约为1×10⁻¹⁰ M）。由于随着向自主性的转变，雌激素、孕酮受体以及催乳素受体以协同方式减少，自主性生长可能是由于受体丧失或肿瘤中自主性细胞相对比例增加所致。
