Stenman U H, Laatikainen T, Salminen K, Huhtala M L, Leppäluoto J
J Chromatogr. 1984 Aug 3;297:399-403. doi: 10.1016/s0021-9673(01)89061-0.
Cation-exchange high-performance liquid chromatography (HPLC) was used to increase the sensitivity and specificity of the radioimmunoassay of plasma beta-endorphin. Proteins were precipitated from a 0.5 to 2.5 ml sample of plasma with 60% acetonitrile at pH 4.7. The supernatant was subjected to cation-exchange HPLC. Gradient elution with volatile buffers was used to separate beta-endorphin from beta-lipotropin. The beta-endorphin fraction (1.8 ml) was concentrated by lyophilization and subjected to radioimmunoassay. In healthy pregnant women at labour plasma concentration of beta-endorphin varied from 105 to 403 pg/ml. In healthy non-pregnant women plasma concentration of beta-endorphin was low, exceeding the detection limit (4 pg/ml) of the assay in only one of the 7 subjects studied.
采用阳离子交换高效液相色谱法（HPLC）提高血浆β-内啡肽放射免疫测定的灵敏度和特异性。用pH 4.7的60%乙腈从0.5至2.5 ml血浆样本中沉淀蛋白质。上清液进行阳离子交换HPLC分析。使用挥发性缓冲液进行梯度洗脱，以将β-内啡肽与β-促脂素分离。β-内啡肽组分（1.8 ml）通过冻干浓缩并进行放射免疫测定。在分娩时的健康孕妇中，β-内啡肽的血浆浓度在105至403 pg/ml之间变化。在健康非孕妇中，β-内啡肽的血浆浓度较低，在所研究的7名受试者中只有1名超过了该测定的检测限（4 pg/ml）。
