metyraponin

Metyrapone is a pharmaceutical compound that inhibits the enzyme 11 beta-hydroxylase. This enzyme is crucial in the adrenal glands for the final step in cortisol synthesis. By blocking this enzyme, metyrapone reduces the production of cortisol. This reduction in cortisol triggers a feedback mechanism in the pituitary gland, leading to an increase in the release of adrenocorticotropic hormone (ACTH). ACTH, in turn, stimulates the adrenal glands to produce more cortisol precursors, such as 11-deoxycortisol.

The primary use of metyrapone is in diagnostic testing to assess the integrity of the hypothalamic-pituitary-adrenal (HPA) axis. Specifically, it is used to evaluate the pituitary gland's ability to respond to low cortisol levels by increasing ACTH production. This is often done to diagnose conditions like Cushing's disease, which involves excessive cortisol production, or secondary adrenal insufficiency, where the pituitary gland is not producing enough ACTH.

Metyrapone is typically administered orally. Due to its mechanism of action, side effects can include nausea, vomiting, dizziness, and headache. More serious side effects, though rare, may involve allergic reactions or worsening of adrenal insufficiency. Its use requires careful medical supervision and monitoring of hormone levels. It is not used as a long-term treatment for any condition.