Neurotensin in plasma: immunochemical and chromatographic character of acid/acetone-soluble material.
Neurotensin in plasma: immunochemical and chromatographic character of acid/acetone-soluble material.
复制标题
血浆中的神经降压素：酸/丙酮可溶性物质的免疫化学和色谱特征。
作者：
R. Carraway;R. Hammer;S. Leeman
使用RIA，我们研究了动物和人血浆的酸/丙酮提取物中存在的神经降压素样（NT样）肽的特性。使用具有不同特异性的四种抗血清测量血浆免疫反应性。抗血清，直接对羧基末端的NT测量更高水平的血浆免疫反应性比NH 2-末端或混合特异性的抗血清。牛血浆提取物的色谱分离显示存在多种物质，其中一种在色谱和免疫化学上与NT无法区分。我们估计该组分的血浆水平约为15-25 fmol/ml，这是使用抗血清HC-8对未分级提取物获得的测量值的30-50%。还鉴定了几种其他组分，它们的表现似乎比NT小，并且似乎与NT共享4至8个COOH末端氨基酸。一个从Sephadex G-25洗脱的区域中的NT样肽先前确定的胃粘膜提取物。将合成NT输注到大鼠中30分钟并没有导致这些NT的COOH末端亲属的形成。我们的研究结果强烈支持血浆中存在NT，并且还表明与NT共享COOH末端同源性的其他肽出现在血浆中，可能来自胃、肝和其他尚未鉴定的来源。
Using a RIA, we have examined the character of the neurotensin-like (NT-like) peptides present in acid/acetone extracts of animal and human plasma. Plasma immunoreactivity was measured using four antisera with different specificities. Antisera which were directed against the COOH-terminus of NT measured higher levels of plasma immunoreactivity than did antisera with NH2-terminal or mixed specificity. Chromatographic fractionation of bovine plasma extracts revealed the presence of multiple substances, one of which was chromatographically and immunochemically indistinguishable from NT. We estimate the plasma level of this component to be about 15-25 fmol/ml, which is 30-50% of the measurement obtained on unfractionated extracts using antiserum HC-8. Several other components were also identified which behaved as though they were smaller than NT and seemed to share with NT four to eight of its COOH-terminal amono acids. One eluted from Sephadex G-25 in the region of the NT-like peptide previously identified in extracts of gastric mucosa. Infusion of synthetic NT into rats for 30 min did not result in the formation of these COOH-terminal relatives of NT. Our results argue strongly for the presence of NT in plasma and also indicate that other peptides, sharing COOH-terminal homologies with NT, appear in plasma, possibly from the stomach, liver, and other as yet unidentified source(s).