Baumann G
Department of Medicine, Northwestern University Medical School, Chicago, Illinois.
Acta Endocrinol (Copenh). 1991;124 Suppl 2:21-6.
Circulating growth hormone binding proteins have recently been recognized in man and certain animals. In man, two specific growth hormone binding proteins have been described, one with high affinity and another with low affinity. The high affinity binding protein corresponds to the extracellular portion of the hepatic growth hormone receptor, whereas the low affinity binding protein appears unrelated to the receptor. Both binding proteins bind one molecule of growth hormone to form complexes of 85 kD (high affinity) and 125 kD (low affinity). The isoelectric points of the two binding proteins are about 5.0 and 7.1, respectively. Most of the complexed growth hormone in plasma is associated with the high affinity binding protein. The binding proteins can be assayed by their specific ability to bind human growth hormone. Generally, plasma is incubated with radiolabelled human growth hormone under standardized conditions, and bound growth hormone is then separated from free growth hormone by size exclusion or ion exchange chromatography, or by charcoal adsorption. Several technical modifications of these fundamental assay designs exist.
循环生长激素结合蛋白最近在人类和某些动物中被发现。在人类中，已描述了两种特异性生长激素结合蛋白，一种具有高亲和力，另一种具有低亲和力。高亲和力结合蛋白对应于肝脏生长激素受体的细胞外部分，而低亲和力结合蛋白似乎与该受体无关。两种结合蛋白均结合一分子生长激素，形成85kD（高亲和力）和125kD（低亲和力）的复合物。两种结合蛋白的等电点分别约为5.0和7.1。血浆中大多数复合生长激素与高亲和力结合蛋白相关。可通过其结合人生长激素的特定能力来检测结合蛋白。一般来说，在标准化条件下将血浆与放射性标记的人生长激素一起孵育，然后通过尺寸排阻色谱法、离子交换色谱法或活性炭吸附法将结合的生长激素与游离生长激素分离。这些基本检测设计有几种技术改进。
