CHARACTERIZATION OF SOMATOTROPIN--RECEPTOR INTERACTIONS

生长激素(生长激素)、催乳素(PRL)和胎盘 催乳素(PL)是一个结构和功能相关的家族 对年度生长和代谢很重要的蛋白质。之间的同源性 这些蛋白质也在相互作用的水平上表达 细胞表面受体，但存在明显的特异性。人生长激素(HGH) 有自己独特的灵长类生体感受器，并将与两者结合 动物的生体和产乳受体。很少有人能很好地理解 关于hGH与HGH相互作用的结构-功能关系 受体或其作用机制，由于一些复杂的 因素(例如生物活性污染物、难以进行的生物检测、多种形式 激素、受体种群的异质性)。以前的研究 胰岛素表明，蛋白质的碘化作用可以改变其活性。 和/或与受体的亲和力。由于研究hGH作用的工作很多 利用hGH的125I-制剂，建议系统地分离、 标准生成的人生长激素的~(125)I-碘异构体的鉴定和表征 加碘程序。凝胶过滤和高密度等技术 高效液相色谱(HPLC)，聚丙烯酰胺凝胶 电泳法、等电聚焦法和纸层析法 将采用电泳法和胰蛋白肽图法 表征起始的hGH和随后的碘异构体。纯净的 示踪剂将被进一步表征为与人淋巴细胞结合， 兔乳腺细胞膜和兔肝细胞膜 乳源性受体以及放射免疫测定和体外试验 使用制备的~(127)I-碘异构体的产乳和产体生物测定。人生长激素 在非灵长类动物中是活跃的，但非灵长类生长激素在人类中不活跃，因此 可用于临床治疗的hGH一直短缺。 生长激素依赖型生长障碍。然而，现在生物合成的甲硫酰-hGH 利用重组DNA技术在大肠杆菌中合成(MhGH) 正在进行测试以允许其在临床上使用。对mhGH的研究将是 与高纯度hGH平行进行的研究和结果 对我们理解生长激素有很大的帮助： 受体的相互作用，以及加速评估的关键 需要mhGH。

The somatotropins (growth hormones, GH), prolactins (PRL) and placental lactogens (PL) form a family of structurally and functionally related proteins important for annual growth ad metabolism. Homologies between these proteins are also expressed at the level of interaction with cell-surface receptors, but distinct specificities exist. Human GH (hGH) has its own specific primate somatogenic receptor and will bind to both somatogenic and lactogenic receptors of animals. Little is well understood concerning the structure-function relationships of hGH interaction with receptor or its mechanism of action, due to a number of complicating factors (e.g. bioactive contaminants, difficult bioassays, multiple forms of the hormone, receptor population heterogeneity). Previous studies of insulin have indicated that iodination of a protein can alter its activity and/or affinity for receptor. Since much work investigating hGH action uses 125I-preparations of hGH, it is proposed to systematically isolate, identify and characterize the 125I-iodoisomers of hGH generated by standard iodination procedures. Techniques such as gel filtration and high performance liquid chromatography (HPLC), polyacrylamide gel electrophoresis, isoelectric focusing, and paper chromatography and electrophoresis, and tryptic peptide mapping will be employed to characterize the starting hGH and subsequent iodoisomers. The purified tracers will be further characterized for binding to human lymphocytes, rabbit mammary gland membrane and rabbit liver membrane somatogenic and lactogenic receptors as well as in radoimmunoassays, and in vitro lactogenic and somatogenic bioassays using prepared 127I-iodoisomers. HGH is active in nonprimates, but nonprimate GH is not active in man, thus there has been a shortage of hGH available for the clinical treatment of GH-dependent growth disorders. Now, however, biosynthetic methionyl-hGH (mhGH) synthesized in E. coli using recombinant DNA technology is undergoing testing to allow its use clinically. Studies of mhGH will be conducted in parallel with those of highly purified hGH and the results should contribute significantly to our understanding of somatotropin: receptor interactions, as well as hasten the evaluation of the critically needed mhGH.