|Molar mass||2933.437 g/mol|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
Cosyntropin (cortrosyn) is a synthetic derivative of adrenocorticotropic hormone (ACTH) that is used in the ACTH stimulation test to evaluate and diagnose cortisol disorders. Cosyntropin contains only the first 24 (of a total 39) amino acids of ACTH but retains full function.
In patients with low cortisol levels or symptoms of adrenocortical insufficiency, cosyntropin can be used to diagnose Addison's disease. A failure for serum cortisol levels to increase after administration of cosyntropin makes a diagnosis of primary adrenocortical insufficiency more likely. An increase in cortisol upon administration of cosyntropin rules out the condition. The test may also be used to assess the function of the adrenal glands after successful treatment for Cushing's syndrome.
Cosyntropin is also used in the opposite situation, when there is aldosterone hypersecretion due to either a unilateral adrenal adenoma (which is treated by surgical removal) or bilateral adrenal hyperplasia (treated by oral spironolactone). A procedure called adrenal venous sampling may be used pre-operatively to localize the source of aldosterone hypersecretion from either adrenal gland. A peripheral intravenous infusion of Cosyntropin before and during the procedure stimulates cortisol production and thereby verifies catheter position.