DHEA

产品名称：DHEA ELISA
产    地：Demeditec 
产品货号：DE3415
产品规格：96 Tests
产品说明：
Special remarks: Dehydroepiandrosterone (DHEA; androstenolone; 3b-hydroxy-5-androsten-17-one) is a C19 steroid produced in the adrenal cortex and, to a lesser extent, gonads. DHEA serves as a precursor in testosterone and estrogen synthesis. Due to the presence of a 17-oxo (rather than hydroxyl) group, DHEA has relatively weak androgenic activity, which has been estimated at ~10% that of testosterone. However in neonates, peripubertal children and in ***** women, circulating DHEA levels may be several-fold higher than testosterone concentrations, and rapid peripheral tissue conversion to more potent androgens (androstenedione and testosterone) and estrogens may occur. Moreover, DHEA has relatively low affinity for sex-hormone binding globulin. These factors may enhance the physiologic biopotency of DHEA.
The physiologic role of DHEA has not been conclusively defined. A variety of in vitro effects, including antiproliferative effects in different cell lines and effects on enzyme-mediated cell metabolism, have been reported. In vivo studies suggest that DHEA may affect cholesterol and lipid metabolism, insulin sensitivity and secretion and immune function. Abnormal DHEA levels have been reported in schizophrenia and obesity. Therapeutic administration of DHEA has been proposed for several conditions, including obesity and cardiovascular disease.
Serum DHEA levels are relatively high in the fetus and neonate, low during childhood, and increase during puberty. Increased levels of DHEA during adrenarche may contribute to the development of secondary sexual hair. Serum DHEA levels progressively decline after the third decade of life. No consistent changes in serum DHEA levels occur during the menstrual cycle or pregnancy; however, parity may lower serum DHEA levels in premenopausal women.
DHEA has a rapid metabolic clearance rate as compared to its sulfated conjugate, DHEA-S. Because of this, serum DHEA levels are 100-1000 fold lower than DHEA-S levels. In addition, serum DHEA levels show significant diurnal variation which is dependent on adrenocorticotrophic hormone (ACTH). Serum DHEA levels increase in response to exogenous ACTH administration.
Measurement of serum DHEA is a useful marker of adrenal androgen synthesis. Abnormally low levels may occur in hypoadrenalism, and elevated levels occur in several conditions; including virilizing adrenal adenoma and carcinoma, 21-hydroxylase and 3b-hydroxysteroid dehydrogenase deficiencies and in some cases of female hirsutism. Since very little DHEA is produced by the gonads, measurement of DHEA levels may aid in the localization of androgen source in virilizing conditions.
This testkit coded DE3415 also can be used for veterinary investigations if the animal sample will be extracted using the following procedure:
Extraction procedure for steroids
We are recommending an extraction procedure as follows.
1.Pipette 1 ml of Ethyl Acetate in a 2.5 ml PP microtube (e.g. from Sarstedt).
2.Add between 5 and 200 µl of your sample.
3.Mix for 2-3 minutes on a vortexer.
4.Centrifuge the microtube briefly in order to achieve a clear separation of the 2 phases.
5.Deep freeze the microtube at -20°C or lower for several hours (or overnight).
6.Decant the organic liquid phase into a new tube which can be used for an evaporation process (the specification of the new tube depends of the specifications of your evaporating device). Be sure that no frozen material will be decanted.
7.Evaporate the organic solvent in an appropriate device at elevated temperature. The boiling point of Ethyl Acetate is 77°C. Please stay clearly below this temperature while evaporating.
8.After evaporating the organic solvent until complete dryness re-dissolve your sample with a diluent. In most cases this will be the zero standard of the ELISA (or RIA) to be used for the quantification of the analyte.
9.The volume of the diluent to be used for the reconstitution depends of the sensitivity of your assay system in relation to the analyte concentration in the primary sample.
10.The dilution (or concentration) factor depends of the volumes you have used in #1 and #7.
There is also a method available for the measurement of free DHEA in saliva. The metabolic activity of any steroid is just represented by the free hormone fraction which represents less than 5% of the total. The non-invasive sampling of saliva samples offers another advantage of salivary testing. Demeditec is offering such a testkit in ELISA format with the catalogue number DESLV3012 (please check in the chapter "saliva testing".
上海玉博生物技术有限公司在为生命科学领域提供丰富的产品与信息资源方面处于国内**地位，公司提供的产品涵盖了二十多个国家近五十万种产品，而且产品的数量与信息在不断的增长和更新，公司提供的产品能够使生命科学工作者加快对生物化学，分子生物学，细胞生物学以及蛋白质组学研究的认知，以及分子诊断和临床医学领域的应用。

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