Hizuka N, Takano K, Asakawa K, Sukegawa I, Fukuda I, Demura H, Iwashita M, Adachi T, Shizume K
Department of Medicine, Tokyo Women's Medical College, Japan.
Growth Regul. 1991 Jun;1(2):51-5.
A method to measure free form of insulin-like growth factor I (IGF-I) in human plasma using octadecylsilyl silica (Sep-Pak C18) cartridge has been developed. IGF-I was adsorbed by Sep-Pak C18 cartridge and eluted with 75% ethanol--0.01 M HCl. Labeled and non-labeled IGF-I were recovered in yields 92.5 +/- 2.1% (Mean +/- SEM) and 94.4 +/- 6.3% after adsorption to and elution from the Sep-Pak, respectively. When EDTA plasma was applied to the Sep-Pak, less than 5% of total IGF-I was recovered in the eluate. However, when acid-ethanol extracted plasma was applied to the Sep-Pak, IGF-I was recovered in yields greater than 75% of total IGF-I. When the Sep-Pak eluate was gel filtered, 88.4 +/- 4.0% of immunoreactive IGF-I eluted in the same fraction as synthetic IGF-I did, but the fraction passed through the Sep-Pak was observed as a high molecular weight form (bound form) of IGF-I. These data indicate that this Sep-Pak method does not extract all of the IGF-I in plasma, but extracts mainly the free form IGF-I. Using this method, IGF-I values of free form (fIGF-I) in EDTA plasma were measured. The fIGF-I values in normal adults, patients with acromegaly, and patients with growth hormone (GH)-deficiency were 2.4 +/- 0.1, 13.8 +/- 1.6, and 1.1 +/- 0.1 ng/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
已开发出一种使用十八烷基硅烷硅胶（Sep-Pak C18）柱测定人血浆中游离形式胰岛素样生长因子I（IGF-I）的方法。IGF-I被Sep-Pak C18柱吸附，并用75%乙醇-0.01M盐酸洗脱。标记和未标记的IGF-I在吸附到Sep-Pak柱并洗脱后，回收率分别为92.5±2.1%（平均值±标准误）和94.4±6.3%。当将EDTA血浆应用于Sep-Pak柱时，洗脱液中回收的IGF-I总量不到5%。然而，当将酸乙醇提取的血浆应用于Sep-Pak柱时，IGF-I的回收率大于IGF-I总量的75%。当Sep-Pak柱洗脱液进行凝胶过滤时，88.4±4.0%的免疫反应性IGF-I与合成IGF-I在同一馏分中洗脱，但通过Sep-Pak柱的馏分被观察为IGF-I的高分子量形式（结合形式）。这些数据表明，这种Sep-Pak柱方法并未提取出血浆中所有的IGF-I，而是主要提取游离形式的IGF-I。使用该方法测定了EDTA血浆中游离形式IGF-I（fIGF-I）的值。正常成年人、肢端肥大症患者和生长激素（GH）缺乏患者的fIGF-I值分别为2.4±0.1、13.8±1.6和1.1±0.1ng/ml。（摘要截短于250字）
