Fang V S, Refetoff S
J Clin Endocrinol Metab. 1978 Oct;47(4):780-7. doi: 10.1210/jcem-47-4-780.
A patient with hypopituitarism and an unusually large chromophobe adenoma which secreted an enormous amount of human PRL (hPRL) provided us with a unique opportunity to study the heterogeneity of hPRL. Serum samples obtained before and after surgery as well as pituitary extract were studied. Each sample contained three distinct hPRL peaks on gel filtration designated as big medium, and small. The hPRL moiety of each peak fraction was stable in size, immunoreactivity, and bioreactivity, indicating that the polymorphic hPRL components, once formed, were not interconvertible. As the relative proportion of medium and small hPRL components in all blood samples obtained before surgery and in the pituitary tumor extracts were similar, it seems that these two forms of hPRL originate from the tumor. However, there was a lack of correlation between big, medium, and small hPRL in samples obtained before and 1 yr after surgery. Also, increasing amounts of radioactive substance similar to increasing amounts of radioactive substance similar to big PRL were formed by exposure of 125I-labeled small PRL to progressively larger concentrations of serum. Thus, only small and possibly medium PRL are secretory products.
一名患有垂体功能减退症且伴有异常大的嫌色细胞瘤（该肿瘤分泌大量人催乳素（hPRL））的患者为我们提供了一个研究hPRL异质性的独特机会。我们研究了手术前后采集的血清样本以及垂体提取物。每个样本在凝胶过滤中都含有三个不同的hPRL峰，分别称为大、中、小峰。每个峰组分的hPRL部分在大小、免疫反应性和生物活性方面都很稳定，这表明多态性hPRL组分一旦形成就不能相互转化。由于手术前采集的所有血液样本以及垂体肿瘤提取物中中、小hPRL组分的相对比例相似，看来这两种形式的hPRL起源于肿瘤。然而，手术前和术后1年采集的样本中，大、中、小hPRL之间缺乏相关性。此外，通过将125I标记的小PRL暴露于浓度逐渐升高的血清中，会形成与大PRL类似的放射性物质，且其量不断增加。因此，只有小PRL以及可能的中PRL是分泌产物。
