ACTH is the adrenocorticotropic hormone or the corticotropin called. It is produced in the cells of the anterior pituitary (front lobe of the pituitary gland) under the influence of CRH (corticotropin-releasing hormone). ACTH, in turn, controls the biosynthesis and release of hormones from the adrenal cortex.
The ACTH short test (Synacten test) describes a test procedure to determine whether the adrenal glands have cortisol functional reserves (ie, significant cortisol release).
The procedure
Material Needed
- Blood serum
Preparation of the patient
- Take basal cortisol at 8 a.m.
- Then administer 25 I.U. (= 250 μg) ACTH slowly i. v. (hypersensitivity reactions are possible).
- After 30, 60 and 90 minutes, renewed blood sampling to determine the stimulation values.
Interfering factors
- None known
Normal value
| Normal value | Increase in cortisol after stimulation to > 20 μg/dl (550 mmol/l) |
Indications
- Suspected adrenocortical insufficiency.
- Evidence of heterogeneous 21-hydroxylase deficiency (see below).
- Detection of defects in steroid biosynthesis.
- Suspicion of Cushing’s syndrome – clinical picture caused by an excess of glucocorticoids.
Interpretation
Interpretation – excessive increase
- Cushing’s disease
Interpretation – decreased increase
- Secondary adrenocortical insufficiency
- Adrenogenital syndrome (AGS) with 21-hydroxylase deficiency, or 20,2-desmolase deficiency or 11-β-hydroxylase deficiency – autosomal recessive inherited metabolic disorder characterized by disorders of hormone synthesis in the adrenal cortex. These disorders lead to a deficiency of aldosterone and cortisol.
Interpretation – no increase
- Addison’s disease (primary adrenocortical insufficiency).
- Atrophy of the adrenal cortex, mainly due to long-term therapy with glucocorticoids (cortisone).
