预期应用
ELISA法定量测定人血清、血浆或其它相关液体中脱氢表雄酮(DHEA)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DHEA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DHEA抗原、生物素化的抗人DHEA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DHEA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 Human Dehydroepiandrosterone (DHEA) concentrations in cell culture supernates, serum and plasma.
Introduction
Dehydroepiandrosterone (DHEA), is a natural steroid prohormone produced from cholesterol by the adrenal glands, the gonads, adipose tissue, brain and in the skin (by an autocrine mechanism)]. DHEA is the precursor of androstenedione, testosterone and estrogen. It is the most abundant hormone in the human body.
DHEA is commonly available in health food stores, pharmacies, and many groceries. DHEA is a steroid hormone made by the adrenal glands that acts on the body much like testosterone and is converted into testosterone and estrogen. DHEA and its sulfate (DHEAS) are abundant in the body, but their normal roles are not fully understood.Blood levels of DHEA and DHEAS decline with age. The favorable clinical and immunological effects of DHEA associated with lupus have not been achieved for people with rheumatoid arthritis.
DHEA is produced from cholesterol through two cytochrome P450 enzymes. Cholesterol is converted to pregnenolone by the enzyme P450 scc (side chain cleavage) and then another enzyme CYP17A1 converts pregnenolone to 17α-Hydroxypregnenolone and then to DHEA. In humans DHEA is the dominant steroid hormone and precursor of all sex steroids. Humans produce DHEA in greater quantity than any other species. Even non-human primates have not much more than 10% the relative serum level of DHEA seen in humans. The fact that rodents produce so little DHEA makes the results of experiments conducted with these laboratory animals very controversial.
DHEA production is very high during fetal life by the fetal adrenal glands, declines after birth and remains low during childhood. Production begins around 6 years of age, increasing in quantity until peaking in early adulthood, around the age of 25, and declines afterwards to approximately 10% of peak levels by age 80. It is theorized by some that this decline may be due to reduced oxygen and glucose supply to the adrenal glands as a result of age-related atherosclerosis.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for DHEA has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any DHEA present is bound by the immobilized antibody. An enzyme-linked polyclonal antibody specific for DHEA 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 DHEA bound in the initial step. The color development is stopped and the intensity of the color is measured.
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