title: Plasma ACTH in diagnosis and control of adrenal disorders.
abstract: Unstimulated plasma ACTH concentrations remain at or below the detection limit of conventional immunoassays. Grossly elevated ACTH concentrations are diagnostic in suspected adrenal insufficiency, remain elevated well above 200 ng/l during substitution therapy and obviate the need of further tests. For the diagnosis of secondary adrenal failure, plasma ACTH, cortisol and 11-desoxycortisol response to a single midnight dose of metyrapone (1.2 g/m2 = 30 mg/kg) discriminates between a normal (morning ACTH above 100 ng/l), diminished (morning ACTH detectable, but below 100 ng/l), and an absent (ACTH below 20 - 40 ng/l) ACTH reserve. In congenital adrenal hyperplasia, plasma ACTH concentrations mirror, together with 17-alpha-hydroxyprogesterone, the extent of ACTH suppression. Elevated ACTH concentrations were suppressed by prednisolone (25%), dexamethasone (2% of the hydrocortisone dose) or by addition of cyproterone acetate (100 mg/m2/day). Using selective venous catheterisation in clinically and biochemically proven Cushing's syndromes, a pituitary adenoma could be identified and localized in 6 of 8 patients by measuring ACTH concentrations in the left and right petrosal sinus before and after stimulation with corticotrophin releasing hormone.
mesh_terms: D019326:17-alpha-Hydroxyprogesterone; D000236:Adenoma / Q000175:diagnosis; D000307:Adrenal Gland Diseases / Q000097:blood / Q000175:diagnosis*; D000312:Adrenal Hyperplasia, Congenital / Q000175:diagnosis; D000309:Adrenal Insufficiency / Q000175:diagnosis; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000328:Adult; D002648:Child; D003350:Cortodoxone / Q000097:blood; D003480:Cushing Syndrome / Q000175:diagnosis; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006908:Hydroxyprogesterones / Q000097:blood; D008797:Metyrapone; D010911:Pituitary Neoplasms / Q000175:diagnosis
chemical_list: D006908:Hydroxyprogesterones; D019326:17-alpha-Hydroxyprogesterone; D000324:Adrenocorticotropic Hormone; D003350:Cortodoxone; D006854:Hydrocortisone; D008797:Metyrapone