Primary mineralocorticoid secreted by the adrenal zona glomerulosa. The role of aldosterone in metabolism is the control of sodium and potassium. Regulating sodium ion concentration, in turn, regulates fluid volume. Aldosterone acts to decrease excretion of sodium and increase the excretion of potassium at the kidney, sweat glands, and salivary glands. This assay is useful in the investigation of Primary Aldosteronism (Adrenal Adenoma / Carcinoma and Adrenal Cortical Hyperplasia) and Secondary Aldosteronism (Renovascular disease, salt depletion, potassium loading, cardiac failure with ascitis and pregnancy).