Adrenocorticotropic Hormone (ACTH, Corticotropin), Plasma/Serum

Clinical Significance:
Adrenocorticotropic Hormone (ACTH) is secreted by the anterior pituitary gland. The major effects of ACTH are the regulation of the adrenal gland to release glucocorticoids primarily cortisol, mineralocorticoids including aldosterone, and sex steroids to supplement those produced by the gonads. ACTH secretion is controlled by corticotropin releasing factor from the hypothalamus and by negative feedback control by the glucocorticoids. Increased levels of ACTH lead to hypercortisolism, hypertension, edema and increased pigmentation. Elevated levels of ACTH are seen in Cushing’s syndrome, ectopic ACTH tumors, adrenal atrophy, adrenal adenoma or carcinoma, congenital adrenal hyperplasia, and stress. Decreased levels occur in Addison’s disease, secondary adrenal hyperplasia, hypopituitarism, hypothalamic failure and in patients on glucocorticoid therapy. Urine ACTH measurements integrate ACTH secretion over a 24 hour period minimizing the effect of diurnal variation found in plasma or serum levels.

Reference Range:
10 – 75 pg/mL

ACTH is measured by radioimmunoassay.

Patient Preparation:
Patient should be fasting 10-12 hours, if possible, prior to the collection of specimen. Cortrosyn, dexamethasone, corticosteroids, and other medications that may affect pituitary secretion should be discontinued, if possible, for at least 48 hours prior to collection of specimen. Morning specimens are preferred.

Specimen Collection:
5ml of serum, EDTA plasma or heparinzed plasma should be collected and separated as soon as possible and frozen prior to shipping. No special preservatives are required. Specimens should be frozen.

Shipping Instructions:
ACTH specimens should be shipped frozen in dry ice.

1. H Hohtari, K Salminen-Lappalainen, and T Laatikainen. Response of Plasma Endorphins, Corticotropin, Cortisol, and Luteinizing Hormone in the Corticotropin-Releasing Hormone Stimulation Test in Eumenorrheic and Amenorrheic Athletes. Fertility and Sterility 55: 276-280, 1991.

2. E Carmina, JH Levin, G Malizia, and RA Lobo. Ovine Corticotropin-Releasing Factor and Dexamethasone Responses in Hyperandrogenic Women. Fertility and Sterility 54: 251-254, 1990.