Systematic search on a smooth muscle stimulant peptide in mammalian kidney.

在对哺乳动物细胞系中未知生物活性多肽的调查中，我们在佛波酯处理的人单核细胞系THP-1的培养液中检测到了最有效的鸡直肠松弛活性。因此，我们从THP-1的培养液中进行了纯化，分离出了四个对雏鸡直肠具有强烈松弛作用的多肽。通过微序列分析，这些多肽的氨基酸序列被推测为一系列人C型利钠肽(CNP)，从CNP-22的N端延伸出几个氨基酸。此外，在THP-1细胞中检测到CNP基因的表达，并且在佛波酯的刺激下，CNP基因的表达和培养上清液中CNP的浓度显著增加。在THP-1单核细胞系中证明CNP的产生表明，CNP在免疫和血管系统中也作为局部化学介质发挥作用，尽管CNP被认为是一种神经肽，仅在CENT…中起作用我们也一直在寻找可能与循环控制有关的多肽，使用一种监测血小板cAMP升高活性的测定系统。在本研究中，我们在人嗜铬细胞瘤提取物中发现了一种新的降压肽。由于这种多肽在正常肾上腺髓质和肾上腺髓质嗜铬细胞瘤组织中含量丰富，因此被命名为“肾上腺髓质素”。该多肽由52个氨基酸组成，分子内有一个二硫键，与降钙素基因相关多肽有轻微的同源性。由于肾上腺髓质素在嗜铬细胞瘤组织中含量丰富，因此构建了嗜铬细胞瘤的cDNA文库，并对其编码肾上腺髓质素前体的cDNA克隆进行了分离和测序。人肾上腺髓质素(人肾上腺髓质素前体)的前体全长185个氨基酸，包括一个肾上腺髓质素序列，然后是甘氨酸(酰胺供体)。ProAdrenomedullin(ProAm)含有一个独特的20个氨基酸序列，在N-末端有Gly-Lys-Arg。这可能是一个新的20个残基的肽“前肾上腺髓质素N-末端20肽”(ProAM-N20)与酰胺化的羧基天门冬氨酸。RNA印迹分析发现，人肾上腺髓质素在肾上腺髓质、脑室、肺、肾和嗜铬细胞等组织中高表达，肾上腺髓质素在多种组织中广泛分布，并在血液中有相当浓度的循环。这些数据表明，肾上腺髓质素是一种参与循环控制的新激素。肾上腺髓质素的出现提示可能存在一种新的循环控制系统。较少

In a survey for unknown bioactive peptides in mammalian cell lines, we detected the most potent chick rectum relaxant activity in the culture medium of phorbol ester-treated human monocytic cell line, THP-1. Thus, we started purification from the culture medium of THP-1 and isolated four peptides exhibiting strong relaxant effects on chick rectum. By microsequence analysis, amino acid sequences of these peptides were deduced to be a series of human C-type natriuretic peptides (CNPs) with several amino acid elongations from the N-terminus of CNP-22. Furthermore, CNP mRNA was detected in the THP-1 cells, and expression of CNP gene and CNP concentration in the culture medium were shown to be greatly increased by the stimulation of phorbol ester.The demonstration of CNP production in THP-1 monocytic cell line suggests that CNP also functions as a local chemical mediator in the immune and vascular system, although CNP has been recognized to function as a neuropeptide exclusively in the cent … More ral nervous system.We have also been searching for peptides which may be relevant to circulation control, using an assay system which monitors the elevating activty of platelet cAMP.In the present study, we discovered a novel hypotensive peptide in human pheochromocytoma extract. Since this peptide is abundant in normal adrenal medulla as well as in pheochoromocytoma tissue arising from adrenal medulla, it was designated "adrenomedullin". The peptide, consisting of 52 amino acids, has one intramolecular disulfide bond and shows slight homology with calcitonin gene related peptide. It was found to elicit a potent and long lasting hypotensive effect in anesthetized rat.Since adrenomedullin was abundant in pheochromocytoma tissue, the cDNA library of pheochromocytoma was constructed, and the cDNA clone concoding an adrenomedullin precursor was isolated and sequencd. The precursor for human adrenomedullin (human preproadrenomedullin) is 185 amino acids in length, including an adrenomedullin sequence, followed by a glycine (the amide donor). Proadrenomedullin (proAM) contains a unique twenty amino acid sequence followed by Gly-Lys-Arg in the N- terminal region. It is possible that a novel 20 residues peptide "proadrenomedullin N- terminal 20 peptide" (proAM-N20) with an amidated carboxy teminus is processed from the precursor. By RNA blot anaylysis, human adrenomedullin mRNA was found to be highly expressed in several tissues including adrenal medulla, ventricle, lung and kidney as well as pheochromocytoma.Adrenomedullin was widely distributed in several tissues and circulates in blood in a considerable concentration. These data suggest that adrenomedullin is a new hormone participating in circulation control. Occurrence of adrenomedullin indicates the possible existence of a novel system for circulation control. Less