预期应用
ELISA法定量测定大鼠血清、血浆或其它相关液体中 甲状旁腺激素相关蛋白(PTHrP)含量。
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PTHrP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PTHrP抗原、生物素化的抗大鼠PTHrP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PTHrP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 Parathyroid Hormone-Like Related Protein（PTHrP）concentrations in serum ,plasma and cell culture supernates.
Introduction
Parathyroid hormone-related protein (PTHrP) is actually a family of protein hormones produced by most if not all tissues in the body. A segment of PHRH is closely related to parathyroid hormone, and hence its name, but PHRH peptides have a much broader spectrum of effects. Parathyroid hormone and some of the PTHrP peptides bind to the same receptor, but PTHrP peptides also bind to several other receptors. PHRH was discovered as a protein secreted by certain tumors that caused hypercalcemia in affected patients. It was soon shown that the uncontrolled secretion of PHRH by many tumor cells induces hypercalcemia by stimulating resorption of calcium from bone and suppressing calcium loss in urine, similar to what is seen with hyperparathyroidism. However, it quickly become apparent that PHRH had many activities not seen with parathyroid hormone.PTHrP is a protein secreted by some cancer cells leading to humeral hypercalcaemia of malignancy (HHM). PTHrP is produced commonly in patients with breast or prostate cancer and occasionally in patients with myeloma. PTHrP shares the same 13 N-terminal amino acids as parathyroid homone (PTH), however the size and remaining amino acids are quite distinct. PTHrP is larger than PTH and contains between 139 and 173 amino acids compared to 84 for PTH.
PTHrP shares many actions with PTH leading to increased calcium release from bone, reduced renal calcium excretion and reduced renal phosphate reabsorption. However PTHrP does not produce the normal anion gap metabolic acidosis commonly found with hyperparathyroidism.PTHrP has important physiological roles in normal growth and development, particularly in the area of bone formation.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for PTHrP has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any PTHrP present is bound by the immobilized antibody. After washing away any unbound substances, an enzyme-linked polyclonal antibody specific for PTHrP 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 PTHrP bound in the initial step. The color development is stopped and the intensity of the color is measured.
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