Evidence for the presence of human chorionic gonadotropin (hCG) and free beta-subunit of hCG in the human pituitary.
Evidence for the presence of human chorionic gonadotropin (hCG) and free beta-subunit of hCG in the human pituitary.
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人垂体中存在人绒毛膜促性腺激素 (hCG) 和 hCG 游离 β 亚基的证据。
DOI：
10.1210/jcem-71-1-179
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Klaus Mann
中科院分区：
文献类型：
--
作者：
R. Hoermann;G. Spoettl;Roy Moncayo;Klaus Mann
以前的研究表明，除了其他糖蛋白激素外，脑下垂体可能还会产生游离的α-亚基和少量的hCG。由于hCG的合成需要两个亚基的同时存在，我们研究了人脑垂体中除了完整的hCG外，还存在游离的hCGβ亚基。我们用分级硫酸铵沉淀法处理脑垂体提取物，然后用Sephadex G-100和Ultroguel ACA 44进行顺序层析。对得到的组分与一组针对hCG、hCG的β亚基、α亚基或hCG/1H的多克隆和单抗的反应性进行了评估。除了预期的黄体生成素和α-亚基外，我们还检测到从柱子中洗脱出来的物质，其位置与125I-hCG示踪剂和hCG-β(NIH CR123-β)非常相似，并且在特定的免疫放射分析中分别显示了holo-hCG和hCG-β的免疫反应。来自绝经后妇女尿液的Holo-hCG和hCG-beta材料在柱子上表现出类似于脑垂体型的行为。在hCG抗体偶联的Sepharose柱上亲和层析，可使垂体的hCG-β亚基和游离的hCG-β亚基的活性均得到丰富(约500倍)。颗粒凝胶等电聚焦时，hCG和hCG-β亚基分别集中在妊娠hCG和妊娠hCG-β亚基的等电点范围内。与妊娠hCG一样，大多数(75%)的垂体hCG与ConA-Sepharose柱结合；然而，ConA非结合的hCG部分(约25%)远高于妊娠hCG。根据免疫反应性，我们的脑垂体提取液中hCG的含量估计为60微克/克，游离β亚基的含量为45微克/克，作为比较，黄体生成素约为20毫克/克，游离的α亚基为1.6 mg/g。此外，我们可以证明在两名绝经后妇女的单个脑垂体的氯化钠提取液中同时存在完整的hCG和游离的hCG-β亚基的免疫反应性。在这些研究中，发现了第二种hCG-β免疫反应物质，远远落后于hCG-β-位置。纯化的促黄体生成素-β-亚基在hCG-β-IRMA中有1.56%的交叉反应，层析得到的洗脱模式与hCG-β免疫活性物质的洗脱模式明显不同。
Previous studies have indicated that the pituitary gland may produce free alpha-subunit and small quantities of hCG in addition to other glycoprotein hormones. Since synthesis of holo-hCG requires the presence of both subunits, we have investigated the occurrence in human pituitary of free beta-subunit of hCG, in addition to intact holo-hCG. We processed a pituitary extract by fractionated ammonium sulfate precipitation followed by sequential chromatography on Sephadex G-100 and Ultrogel AcA 44. The fractions obtained were assessed for their reactivities with a panel of polyclonal and monoclonal antibodies specific for holo-hCG, beta-subunit of hCG, alpha-subunit, or hCG/LH. In addition to the expected LH and alpha-subunit, we detected materials which eluted from the column in positions very similar to those of cochromatographed 125I-hCG tracer and hCG-beta (NIH CR123-beta), and which showed immunoreactivity in specific immunoradiometric assays for holo-hCG and hCG-beta, respectively. Holo-hCG and hCG-beta material derived from the urine of a postmenopausal woman showed behaviors on the column similar to the pituitary forms. Both the pituitary holo-hCG- and free hCG-beta-subunit activity could be enriched (approximately 500 times) by affinity chromatography on an hCG antibody-coupled Sepharose column. When subjected to isoelectric focusing in granulated gel holo-hCG and hCG-beta-subunit of pituitary origin were focused in the pI-range of pregnancy hCG and pregnancy hCG-beta-subunit, respectively. Like pregnancy hCG, most (75%) of the pituitary hCG was bound to a column of Con A-Sepharose; however, the Con A-nonbinding hCG fraction (approximately 25%) was much higher than that found in pregnancy hCG. On the basis of immunoreactivities, the content of holo-hCG in our pituitary extract was estimated to be 60 micrograms/g, and that of free beta-subunit 45 micrograms/g; for comparison, LH was approximately 20 mg/g, and free alpha-subunit 1.6 mg/g. In addition, we could demonstrate the presence of both holo-hCG- and free hCG-beta-subunit-like immunoreactivity in NaCl-extracts from single pituitaries of two postmenopausal women. In these studies a second hCG-beta-immunoreactive material eluting far behind the hCG-beta-position was found. Chromatography of purified LH-beta-subunit, which crossreacts 1.56% in the hCG-beta IRMA, yielded an elution pattern clearly distinguishable from that of the hCG-beta-immunoreactive substances.(ABSTRACT TRUNCATED AT 400 WORDS)