PNMT and major depressive disorder: PNMT principally catalyzes the conversion of norepinephrineto epinephrine (Figure 2A) and is mainly involved in the stress response.20,21 Epinephrine is strongly correlated with mood alteration and depression.22−25 In addition, several studies indicate a role for this hormone inthe control of erection.26−30 Overall, these findings prompted us to consider PNMT as a potentiallyrelevant factor in FIN side effects.