1.NounA compound that inhibits the enzyme 17β-hydroxylase and prevents synthesis of glucocorticoids and mineralocorticoids by the adrenal gland, used chiefly for assessment of feedback control of the hypothalamic–pituitary axis in adrenal disease, and sometimes in the treatment of Cushing's syndrome and resistant edema; 2-methyl-1,2-di-3-pyridyl-1-propanone, C5H4N·CO·C(CH3)2·C5H4N.