Phillips L S, Bajaj V R, Fusco A C, Keery K M, Goldstein S
Int J Biochem. 1985;17(5):597-603. doi: 10.1016/0020-711x(85)90291-5.
Bioassayable somatomedins and somatomedin inhibitors were examined after chromatographic separation, using serum from normal rats (enriched in somatomedins) and diabetic rats (enriched in somatomedin inhibitors). At neutral pH, gel filtration on Sephacryl S-300 revealed somatomedins at mol. wt approximately 140,000 (presumably carrier-bound) and inhibitors at mol. wts approximately 250,000, approximately 24,000 and approximately 1,000. At acid pH, gel filtration on Sephadex G-50 revealed somatomedins at mol. wt approximately 8,000 (presumably carrier-free) and a single inhibitor at mol. wt approximately 21,000. Ion exchange chromatography revealed that the inhibitor(s) may be more acidic than the somatomedins, but only low quantities of somatomedins were recovered. Sephadex G-50 fractionation was applied to pathophysiologic models in rats: 3 days of fasting were associated with a 62% fall in somatomedins and a 159% rise in inhibitors; 2 days of diabetes were associated with a 60% fall in somatomedins and a 344% rise in inhibitors. Since chromatography on Sephadex G-50 at pH 2.4 appears to provide adequate separation of somatomedins and somatomedin inhibitors with good estimated recovery of biological activity, this simple approach may be a probe useful in examining the regulation of somatomedins and somatomedin inhibitors in vivo.
利用正常大鼠（富含生长调节素）和糖尿病大鼠（富含生长调节素抑制剂）的血清，在色谱分离后检测了具有生物活性的生长调节素和生长调节素抑制剂。在中性pH条件下，在Sephacryl S - 300上进行凝胶过滤，结果显示生长调节素的分子量约为140,000（可能与载体结合），抑制剂的分子量约为250,000、约24,000和约1,000。在酸性pH条件下，在Sephadex G - 50上进行凝胶过滤，结果显示生长调节素的分子量约为8,000（可能无载体），且有一种分子量约为21,000的单一抑制剂。离子交换色谱显示抑制剂可能比生长调节素更具酸性，但仅回收了少量的生长调节素。Sephadex G - 50分级分离应用于大鼠的病理生理模型：禁食3天与生长调节素下降62%和抑制剂上升159%有关；糖尿病2天与生长调节素下降60%和抑制剂上升344%有关。由于在pH 2.4条件下在Sephadex G - 50上进行色谱分析似乎能充分分离生长调节素和生长调节素抑制剂，且生物活性的估计回收率良好，这种简单方法可能是一种有助于研究体内生长调节素和生长调节素抑制剂调节的有用探针。
