Stolar M W, Baumann G, Vance M L, Thorner M O
J Clin Endocrinol Metab. 1984 Aug;59(2):235-9. doi: 10.1210/jcem-59-2-235.
Human GH (hGH) in the circulation of acromegalic patients and pharmacologically stimulated normal subjects consists of several monomeric and oligomeric molecular forms. However, little is known about the nature of plasma hGH under physiological conditions. We examined the molecular composition of plasma hGH secreted in response to synthetic human pancreatic tumor GRF-(1-40) (hpGRF-40), a peptide closely resembling or identical to hypothalamic GRF. The peptide (10 micrograms/kg) was injected iv into six normal men, and blood was obtained 30 min later. Plasma hGH was characterized by gel filtration and by polyacrylamide gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and isoelectric focusing after extraction from plasma by immunoadsorbent chromatography. At least 53% of hGH eluted as little (monomeric) hGH, 27% as big (dimeric) hGH, and 20% or less as big-big (oligomeric and spurious) hGH during gel filtration. Among the monomeric forms, the 22,000-dalton form was predominant (83%), with smaller quantities of the 20,000-dalton variant (11%), and one or more unidentified acidic forms (N alpha-acetylated, deamidated, or cleaved hGH) (6%) also present. The molecular composition of plasma hGH secreted in response to hpGRF-40 is similar to that released after pharmacological stimuli or that circulating in acromegaly.
肢端肥大症患者以及经药物刺激的正常受试者循环中的人生长激素（hGH）由几种单体和寡聚分子形式组成。然而，关于生理条件下血浆hGH的性质却知之甚少。我们检测了响应合成人胰腺肿瘤GRF-(1-40)（hpGRF-40，一种与下丘脑GRF相似或相同的肽）分泌的血浆hGH的分子组成。将该肽（10微克/千克）静脉注射到6名正常男性体内，30分钟后采集血液。血浆hGH通过凝胶过滤、聚丙烯酰胺凝胶电泳、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳以及从血浆中通过免疫吸附色谱法提取后进行等电聚焦来进行表征。在凝胶过滤过程中，至少53%的hGH以小分子（单体）hGH形式洗脱，27%以大分子（二聚体）hGH形式洗脱，20%或更少以大大分子（寡聚体和假分子）hGH形式洗脱。在单体形式中，22,000道尔顿的形式占主导（83%），还有少量20,000道尔顿的变体（11%），并且还存在一种或多种未鉴定的酸性形式（Nα-乙酰化、脱酰胺化或裂解的hGH）（6%）。响应hpGRF-40分泌的血浆hGH的分子组成与药物刺激后释放的或肢端肥大症患者循环中的hGH相似。
