Mepyrapone | definition of mepyrapone by Medical dictionary
metyrapone (redirected from mepyrapone)
a synthetic compound that selectively inhibits an enzyme responsible for the biosynthesis of corticosteroids
; it is used as a diagnostic aid in a test of pituitary reserve.
An inhibitor of adrenocortical steroid C-11 β-hydroxylation, administered orally or intravenously to determine the ability of the pituitary gland to increase its secretion of corticotropin; because 11-deoxycorticosteroids, as a consequence of metyrapone administration, only weakly inhibit pituitary corticotropin secretion, the normal pituitary gland will appreciably increase its output of this hormone.
metyrapone An agent used to evaluate the hypothalamus-pituitary-adrenal axis, especially abnormal pituitary activity. Metyrapone inhibits 11-beta-hydroxylase, the final enzyme in cortisol synthesis. The inhibition results in accumulation of 11-deoxycortisol in the adrenal cortex, resulting in decreased negative feedback of ACTH synthesis by the pituitary; it therefore also results in increased ACTH and increased 11-deoxycortisol, as well as its metabolite, tetrahydrocortisol, which is measured in the urine as so-called Porter-Silber compounds.
metyrapone A diagnostic tool for evaluating the hypothalamus-pituitary-adrenal 'axis', especially, abnormal pituitary activity