Cortisol

Quantitatively speaking, the main glucocorticoid product of the adrenal cortex is cortisol (hydrocortisone). Cortisol levels are measured for therapy monitoring (e.g., dexamethasone suppression test in Cushing's syndrome and hormone replacement therapy in Addison's disease) as well as for diagnosing human diseases caused by the overproduction of cortisol in Cushing's syndrome (CS) and the deficiency of adrenal steroid excretion in Addison's disease. The regulation of numerous vital physiological processes, such as energy metabolism, blood pressure and electrolyte balance maintenance, immunomodulation and stress responses, cell proliferation, and cognitive functions, is significantly influenced by cortisol. Stress reactions, mental illnesses, obesity, diabetes, alcoholism, and pregnancy can all result in elevated serum levels, which might make it difficult to diagnose Cushing's syndrome in some patients. Patients with uncommon adrenal enzyme deficiencies and those who have experienced prolonged stress have low cortisol levels.