Aldosterone

The DRG:HYBRiD-XL Aldosterone is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of aldosterone in serum and plasma.Only for use with the DRG:HYBRiD-XL Analyzer.The steroid hormone aldosterone is a potent mineral corticoid that is produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. The synthesis and release are controlled by the renin-angiotensin-aldosterone system (RAAS)1, as well as by plasma potassium concentration 2, the pituitary peptide ACTH, and by the blood pressure via pressure sensitive baroreceptors in the vessel walls of nearly all large arteries of the body 3. Aldosterone binds to mineralocorticoid receptors (MR) and triggers the transcription of hormone-responsive genes. In consequence, aldosterone increases the blood pressure by reabsorption of sodium and water from the distal tubules of the kidney into the blood, secretion of potassium into the urine, and elevation of circulating blood volume. Chronic overproduction and secretion of aldosterone leads to hypertension. Aldosterone activity is reduced in Addison's disease and increased in Conn's syndrome. Measurement of aldosterone levels in serum in conjunction with plasma renin levels (aldosterone/renin-ratio; ARR) can be used to differentiate between primary and secondary aldosteronism 4,8,9. The measurement of aldosterone in concert with selective suppression and stimulation tests can be used to further differentiate primary aldosteronism into two basic types 5: Primary aldosteronism caused by an adenoma of one or both adrenals. Primary aldosteronism caused by adrenal hyperplasia. This differentiation is vital in the treatment and management of the disease. The adrenal adenomas respond well to surgery whereas hyperplastic disease of the adrenals is generally better managed medically 6. In addition, pharmacological modulation of nuclear hormone receptors is a common strategy for the treatment of cardiovasculardisease 7. Therefore, determining the effects of such treatments on the RAAS is of increasing value in evaluating the safety and efficacy of new therapeutics. In summary, the precise and accurate measurement of serum aldosterone by enzyme immunoassay can be an important adjunct to a diagnostic laboratory battery for the differential diagnosis of hypertensive disease.The DRG:HYBRiD-XL Aldosterone Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the principle of competitive binding. The antibody coated wells (ACW) of the reagent cartridges are coated with a polyclonal [rabbit] antibody directed towards a unique antigenic site of the aldosterone molecule. Endogenous aldosterone of a patient sample competes with an aldosterone-horseradish peroxidase conjugate for binding to the coated antibody. After incubation the unbound conjugate is washed off. The amount of bound peroxidase conjugate is inversely proportional to the concentration of aldosterone in the sample. Having added the substrate solution, the intensity of colour developed is inversely proportional to the concentration of aldosterone in the patient sample.