Moore L G, Mylek M E
AgResearch, Wallaceville Animal Research Centre, Upper Hutt, New Zealand.
J Endocrinol. 1993 May;137(2):239-45. doi: 10.1677/joe.0.1370239.
The measurement of insulin-like growth factors (IGFs) in plasma is complicated by the presence of high-affinity IGF-binding proteins (IGFBPs). Consequently, the IGFBPs need to be removed or their IGF-binding effects need to be neutralized prior to assaying samples for IGFs. It was observed that IGFs but not IGFBPs from sheep plasma bind to the size-exclusion gel Sephacryl S-100 HR at a low pH and that the IGFs can subsequently be eluted off at a neutral pH. From this observation a convenient method was developed for the extraction from plasma of ovine (o) IGF-I and -II free from detectable IGFBPs with close to 100% recovery. When assayed in homologous sheep IGF-I and -II radioimmunoassays the Sephacryl-extracted plasma samples gave dose-response curves which were parallel to purified oIGFs. Furthermore, the results obtained by Sephacryl extraction were highly correlated with those found by the established Sephadex G-75 extraction procedure.
血浆中胰岛素样生长因子（IGFs）的测量因高亲和力胰岛素样生长因子结合蛋白（IGFBPs）的存在而变得复杂。因此，在检测IGFs样本之前，需要去除IGFBPs或中和其IGF结合效应。据观察，绵羊血浆中的IGFs而非IGFBPs在低pH值下与排阻凝胶Sephacryl S-100 HR结合，随后IGFs可在中性pH值下洗脱下来。基于这一观察结果，开发了一种便捷的方法，可从血浆中提取不含可检测IGFBPs的绵羊（o）IGF-I和-II，回收率接近100%。在同源绵羊IGF-I和-II放射免疫分析中检测时，经Sephacryl提取的血浆样本给出的剂量反应曲线与纯化的oIGFs平行。此外，通过Sephacryl提取获得的结果与既定的Sephadex G-75提取程序获得的结果高度相关。
