DHEA-S Saliva

GWB-C990DB

Dehydroepiandrosterone sulfate (DHEA-S) is a natural steroid hormone found atop of the kidneys in the human body. DHEA-S derived from enzymatic conversion of DHEA in adrenal and extradrenal tissues. DHEA-S is also produced in the gonads adipose tissue and the brain. It is the most abundant hormone in the human body and it is precursor of all sex steroids. As most DHEA-S is produced by the zona reticularis of the adrenal it is argued that there is a role in the immune and stress response. DHEA-S may have more biologic roles. Its production in the brain suggests that is also has a role as a neurosteroid. The majority of DHEA-S in saliva is non-protein bound and enters the saliva via intracellular mechanisms. Salivary DHEA-S levels are unaffected by salivary flow rate or salivary enzymes. Measurement of serum DHEA-S is a useful marker of adrenal androgen synthesis. Abnormally low levels may occur in have been reported in hypoadrenalism while elevated levels occur in several conditions e. g. virilizing adrenal adenoma and carcinoma 21-hydroxylase and 3& beta; -hydroxysteroid dehydrogenase deficiencies and in some cases of female hirsutism. Women with polycystic ovary syndrome tend to have normal or mildly elevated levels of DHEAS. As very little DHEA-S is produced by the gonads measurement of DHEA-S levels may aid in the localization of androgen source in virilizing conditions. DHEA-S levels show no diurnal variation. Principles of the assay: Microtiter strip wells are precoated with anti-DHEA-S antibodies (solid-phase). DHEA-S in the sample competes with added horseradish peroxidase labelled DHEA-S (enzyme-labelled antigen) for antibody binding. After incubation a bound/free separation is performed by solid-phase washing. The immune complex formed by enzyme-labelled antigen is visualized by adding Tetramethylbenzidine (TMB) substrate which gives a blue reaction product. The intensity of this product is inversely proportional to the amount of DHEA-S in the sample. Sulphuric acid is added to stop the reaction. This produces a yellow endpoint colour. Absorption at 450 nm is read using an ELISA microwell plate reader. Storage and Stability: The reagents are stable up to the expiry date stated on the label when stored at 2. . . 8 & deg; C. Limitations of the Test: Bacterial contamination or repeated freeze-thaw cycles of the specimen may affect the absorbance values. References Joshi U. M. et al. Steroids 34 (1) 35 (1979)Turkes A. et al. J Endocrinol. 81 (2) P165 (1979)Ismail A. A et al. J. Clin. Endocr. Metab. 34 177-184 (1972)Rajkowski K. M et al. Steroids 29 no 5 (1977)Widsdom G. B. Clin. Chem. 22/8 1243 - 1255 (1976)Abraham G. E et al. Obstet. Gynecol. 47(4) 395 (1976)Abraham G. E et al. Obstet. Gynecol. 53(1) 111 (1979)Hopper B. R et al. J. Clin. Endoc. Metab. 40(3) 458 (1975)Winter J. S. D et al. Clin. Obste. and Gynec. 21(1) 67 (1978)Riad D. et al. Endocr. Reviews 3 (4) 304 367 (1978)