 It is specifically an inhibitor of 3β-hydroxysteroid dehydrogenase (3β-HSD).As a result of this action, trilostane blocks the conversion of Δ5-3β-hydroxysteroids, including pregnenolone, 17α-hydroxypregnenolone, dehydroepiandrosterone (DHEA), and androstenediol, into Δ4-3-ketosteroids, including progesterone, 17α-hydroxyprogesterone, androstenedione, and testosterone, respectively.Consequently, trilostane inhibits the production of all classes of steroid hormones, including androgens, estrogens, progestogens, glucocorticoids, and mineralocorticoids.