CYP3A4 and post-traumatic stress disorder: Namely, the authors have postulated a hypothesis that, in PTSD, there is increased activity of the enzyme that metabolizes glucocorticoids, 11β-hydroxysteroid dehydrogenase-2, and of the main metabolizers of glucocorticoids (cortisol in humans and corticosterone in rats), a hepatic-microsomal oxidation enzyme, CYP3A; on the other hand, there is decreased activity of the enzyme that degrades glucocorticoids, 11β-hydroxysteroid dehydrogenase-1 [77].