Differential processing of the two subunits of human choriogonadotropin (hCG) by granulosa cells. I. Preparation and characterization of selectively labeled hCG.-猫眼课题宝

颗粒细胞对人绒毛膜促性腺激素 (hCG) 两个亚基的差异加工。

DOI：

发表时间：

1981

期刊：

Endocrinology

影响因子：

4.8

通讯作者：

中科院分区：

医学2区

文献类型：

作者：

T. Landefeld;M. Byrne;K. Campbell;A. Midgley

hCG的α-和β-亚基被放射性碘标记并与未标记的互补亚基重组。所得的重组激素，选择性地标记在α-或β-亚基，从uncombined的亚基分离的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳，用Triton X-100提取，其特征在于结合分析。用过量受体测定的两种所得选择性标记的重组hCG制剂的最大结合（活性分数）的估计值为0.41和0.59。这些值与将hCG标记为完整分子时获得的值相似。通过四种不同的方法估计重组制剂的比活性，并将所得值与活性分数估计值结合使用，以确定活性游离和结合激素的浓度。使用不同浓度的标记和未标记激素进行结合分析。以三种不同的方式计算平衡解离结合常数（Kd）和受体容量的估计值。两种制剂的容量（52.6和52.7 fmol/mg组织）和Kd（66.6和65.7 pM）的平均估计值无法区分。此外，这些值与先前报告的hCG放射性碘标记完整分子的值相似。充分表征，选择性标记的hCG制剂的可用性提供了新的工具，用于研究这种激素的亚基的作用机制和靶细胞加工。

The alpha- and beta-subunits of hCG were radioiodinated and recombined with unlabeled complementary subunits. The resultant recombined hormones, selectively labeled in either the alpha- or beta-subunit, were separated from unrecombined subunit by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, extracted with Triton X-100, and characterized by binding analysis. The estimates of maximum binding (active fraction) of the two resultant selectively labeled, recombined hCG preparations, determined with excess receptor were 0.41 and 0.59. These values are similar to those obtained when hCG is labeled as an intact molecule. The specific activities of the recombined preparations were estimated by four different methods, and the resulting values were used in combination with the active fraction estimates to determine the concentrations of active free and bound hormone. Binding analyses were run using varying concentrations of both labeled and unlabeled hormone. Estimates of the equilibrium dissociation binding constant (Kd) and receptor capacity were calculated in three different ways. The mean estimates of capacity (52.6 and 52.7 fmol/mg tissue) and Kd (66.6 and 65.7 pM) for the two preparations were indistinguishable. Additionally, these values were similar to values reported previously for hCG radioiodinated as an intact molecule. The availability of well characterized, selectively labeled hCG preparations provides new tools for studying the mechanism of action and the target cell processing of the subunits of this hormone.

Differential processing of subunits of human chorionic gonadotropin by granulosa cells in vivo.