预期应用
ELISA法定量测定大鼠血浆或其它相关液体中内皮素含量。
概述
内皮素是一种由21个氨基酸组成的活性多肽，为目前已知缩血管活性最强的物质。在生理状态下，由于内皮细胞合成内皮素很少且清除速度快，故血浆中内皮素浓度很低。 但在内皮细胞损伤、组织缺血缺氧等情况下，内皮细胞大量合成内皮素并释放入血，成为参与疾病病理生理过程的重要体液因素。
实验原理
本试剂盒应用双抗体夹心酶标免疫分析法测定标本中内皮素水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入内皮素、生物素化的抗大鼠内皮素抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的内皮素呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。
Intended use
This immunoassay kit allows for the specific measurement of rat ET-1 concentrations in plasma.
Introduction
Endothelin-1 (ET-1), a peptide of 21 amino acid residues, is the most potent vasoconstrictive substance known. Originally isolated from porcine aortic endothelial cells, ET-1 is now known to be one of a family of three mammalian vasoactive peptides that also includes Endothelin-2 (ET-2) and Endothelin-3 (ET-3). These related peptides differ from ET-1 at two and six amino acid residue positions, respectively. A fourth peptide, vasoactive intestinal contractor (VIC), is sometimes classified as rat ET-2. All members of the endothelin family contain two essential disulfide bridges and six conserved amino acid residues at the C-terminus. Additionally, all of the endothelin family members are synthesized initially as prepropolypeptides of approximately 200 amino acid residues encoded by separate genes. These are proteolytically cleaved to produce biologically-inactive propolypeptides of approximately 40 amino acid residues termed “big endothelins”. Big ET-1 is cleaved by the proteolytic action of a membrane-bound metalloprotease [endothelin-converting enzyme (ECE-1)] producing the 21 amino acid residue active peptide. The biochemistry and biology of the endothelins have been the subject of several reviews.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for ET-1 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any ET-1 present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for ET-1 is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of ET-1 bound in the initial step. The color development is stopped and the intensity of the color is measured.
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