Lee Y C, Uttenthal L O, Smith H A, Bloom S R
Peptides. 1986 May-Jun;7(3):383-7. doi: 10.1016/0196-9781(86)90002-1.
To study the degradation of neurotensin in plasma in vitro, fresh human plasma was incubated with neurotensin in the presence and absence of the peptidase inhibitors pepstatin A, EDTA, PMSF and aprotinin. The half-time of disappearance of neurotensin at 37 degrees C was calculated to be 226 min in vitro as opposed to 1.4 min in vivo when measured by radioimmunoassay with a C-terminally directed neurotensin antiserum. Both gel filtration and reversed phase high-pressure liquid chromatography (HPLC) showed that the main degradation product of neurotensin in human plasma in vitro was chromatographically and immunologically identical to neurotensin 1-8 and HPLC also demonstrated the formation of neurotensin 1-11. The loss of neurotensin incubated in human plasma in vitro was greatly reduced by EDTA but not by the other peptidase inhibitors tested. In this respect peptidase(s) responsible for the degradation of neurotensin in plasma differ from those present in brain homogenates. EDTA may be of importance in the preservation of neurotensin in plasma samples.
为了在体外研究神经降压素在血浆中的降解情况，将新鲜人血浆与神经降压素在有和没有肽酶抑制剂胃蛋白酶抑制剂A、乙二胺四乙酸（EDTA）、苯甲基磺酰氟（PMSF）和抑肽酶的情况下进行孵育。用C端定向神经降压素抗血清通过放射免疫测定法测得，在37℃时神经降压素在体外消失的半衰期经计算为226分钟，而在体内则为1.4分钟。凝胶过滤和反相高效液相色谱（HPLC）均显示，体外人血浆中神经降压素的主要降解产物在色谱和免疫方面与神经降压素1 - 8相同，并且HPLC还证明了神经降压素1 - 11的形成。在体外人血浆中孵育的神经降压素的损失因EDTA而大大减少，但未被测试的其他肽酶抑制剂减少。在这方面，负责血浆中神经降压素降解的肽酶与脑匀浆中的肽酶不同。EDTA在保存血浆样本中的神经降压素方面可能具有重要意义。
