本试剂盒应用双抗体夹心酶标免疫分析法测定标本中AQP2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AQP2抗原、生物素化的抗大鼠AQP2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AQP2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 AQP2 concentrations in urine, serum, and plasma.
Introduction
Transfer of water across the cellular membrane is mediated by water channel proteins named aquaporins (AQPs). More than 10 isoforms of AQPs have been identified in mammalian cells so far. AQP2 is expressed in the principal cells of the collecting ducts in the kidney and plays a critical role in the urine concentration. A unique feature of AQP2 is that it is stored in the intracellular compartment, and upon stimulation of an antidiuretic hormone (ADH, vasopressin), AQP2 translocates to the apical plasma membrane, where it serves in the uptake of water from the lumen of the collecting duct. The mutation of AQP2 leads to nephrogenic diabetes insipidus, the inability to concentrate urine. In the recessive nephrogenic diabetes insipidus, mutated AQP2 is retained in the endoplasmic reticulum, whereas in the dominant types, it is localized in the Golgi complex, lysosome, or basolateral plasma membrane. These findings clearly show the importance of proper localization and trafficking of AQP2 for its function.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for AQP2 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any AQP2 present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for AQP2 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 AQP2 bound in the initial step. The color
development is stopped and the intensity of the color is measured.
